Interest expense and amortization of deferred financing costs

1,242,408

1,108,551

1,036,178

Total operating expenses

3,311,560

2,972,009

2,717,671

Operating income (loss)

1,044,045

949,216

946,180

(590,682)

(515,032)

(527,128)

Gains (losses) on retirement of long-term obligations

(3,525)

(52,291)

^[2]

(4,157)

^[3]

Interest income

18,761

796

1,906

Other income (expense)

1,994

(8,835)

57,028

Income (loss) from continuing operations before income taxes

470,593

373,854

473,829

Income (Loss) from Continuing Operations

(26,043)

(16,881)

51,457

444,550

356,973

525,286

Income (Loss) from Discontinued Operations, Net of Tax

19,690

^[4],[5],[6]

Net Gain (Loss) from Disposal of Discontinued Operations, Net of Tax

979,359

Income (Loss) from Discontinued Operations, Net of Tax

999,049

Less: Net income (loss) attributable to the noncontrolling interest

444,550

356,973

1,524,335

3,343

Net income (loss) attributable to CCIC stockholders

444,550

356,973

1,520,992

Dividends on preferred stock

(58,294)

(32,991)

(43,988)

Net income (loss) attributable to CCIC common stockholders

386,256

323,982

1,477,004

Net income (loss) from continuing operations

444,550

356,973

1,524,335

Derivative instruments, net of taxes

Interest rate swaps reclassified into results of operations, net of taxes

18,725

Foreign currency translation adjustments

1,899

(1,490)

(14,137)

Amounts reclassified into discontinued operations for foreign currency translation adjustments

(25,678)

Total other comprehensive income (loss)

^[7]

1,899

(1,490)

(21,090)

Comprehensive income (loss) attributable to CCIC stockholders

$ 446,449

$ 355,483

$ 1,503,245

Net income (loss) attributable to CCIC common stockholders, per common share:

$ 1.01

$ 0.95

$ 4.44

Weighted-average common shares outstanding (in thousands):

$ 1.01

$ 0.95

$ 4.42

Basic (in shares)

381,740

340,349

333,002

Diluted (in shares)

383,221

340,879

334,062

Dividends/distributions declared per share of common stock

$ 3.90

$ 3.61

$ 3.35

Discontinued Operations [Member]

Net income (loss) attributable to CCIC common stockholders, per common share:

0.00

2.99

Continuing Operations [Member]

$ 0.00

$ 2.98

Costs of Operations:

Net income (loss) attributable to CCIC common stockholders

$ 386,256

$ 323,982

$ 481,298

Net income (loss) attributable to CCIC common stockholders, per common share:

$ 1.01

$ 0.95

$ 1.45

Cash flows from operating activities:

$ 1.01

$ 0.95

$ 1.44

[1]	Exclusive of depreciation, amortization and accretion shown separately.
[2]	Inclusive of $33.8 million related to the write off of deferred financing costs
[3]	Inclusive of $4.2 million related to the write off of deferred financing costs, premiums and discounts.
[4]	CCAL results are through May 28, 2015, which was the closing date of the Company's sale of CCAL.
[5]	Exclusive of the gain (loss) from disposal of discontinued operations, net of tax, as presented on the consolidated statement of operations.
[6]	No interest expense has been allocated to discontinued operations.
[7]	See the consolidated statement of operations and comprehensive income (loss) for the components of "total other comprehensive income (loss)" and note 9 with respect to the reclassification adjustment.

Consolidated Statement of Cash Flows - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Income (Loss) from Continuing Operations

$ 444,550

$ 356,973

$ 525,286

Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:

(Gains) losses on retirement of long-term obligations

1,242,408

1,108,551

1,036,178

3,525

52,291

^[1]

4,157

^[2]

Gains (Losses) on Settled Swaps

328

2,608

(54,475)

Amortization of deferred financing costs and other non-cash interest

9,368

14,333

37,126

Stock-based compensation expense

91,647

79,338

60,773

Asset write-down charges

17,322

34,453

33,468

Deferred income tax (benefit) provision

14,888

8,603

(60,618)

Other non-cash adjustments, net

(1,648)

2,451

(8,915)

Changes in assets and liabilities, excluding the effects of acquisitions:

Increase (decrease) in accrued interest

34,771

30,044

Increase (decrease) in accounts payable

(34,067)

10,600

(5,287)

Increase (decrease) in deferred revenues, deferred ground lease payables, other accrued liabilities and other liabilities

175,522

195,998

325,880

Decrease (increase) in receivables

60,859

(58,664)

12,668

Decrease (increase) in prepaid expenses, deferred site rental receivables, long-term prepaid rent, restricted cash and other assets

(15,287)

(55,315)

(112,248)

Net cash provided by (used for) operating activities

2,044,186

1,782,264

1,794,025

Cash flows from investing activities:

Payment for acquisitions of businesses, net of cash acquired

(9,260,135)

(556,854)

(1,102,179)

Capital expenditures

(1,228,071)

(873,883)

(908,892)

Receipts from Foreign Currency Swaps

(328)

8,141

54,475

Other investing activities, net

(5,487)

12,364

(3,138)

Net cash provided by (used for) investing activities

(10,494,021)

(1,410,232)

(1,959,734)

Cash flows from financing activities:

Proceeds from issuance of long-term debt

3,092,323

5,201,010

1,000,000

Net proceeds from issuance of common stock

4,221,329

1,325,865

Net proceeds from issuance of preferred stock

1,607,759

Principal payments on debt and other long-term obligations

(118,880)

(95,787)

(102,866)

Purchases and redemptions of long-term debt

(4,044,834)

(1,069,337)

Purchases of common stock

(23,307)

(24,936)

(29,657)

Borrowings under revolving credit facility

2,820,000

3,440,000

1,790,000

Payments under revolving credit facility

(1,840,000)

(4,565,000)

(1,360,000)

Payments for financing costs

(29,240)

(41,533)

(19,642)

Net (increase) decrease in restricted cash

3,808

(7,931)

16,458

Dividends/distributions paid on common stock

(1,508,705)

(1,239,158)

(1,116,444)

Dividends paid on preferred stock

(29,935)

(43,988)

Net cash provided by (used for) financing activities

8,195,152

(96,292)

(935,476)

Net Cash Provided by (Used in) Continuing Operations

(254,683)

275,740

(1,101,185)

Cash Provided by (Used in) Operating Activities, Discontinued Operations

2,700

Cash Provided by (Used in) Investing Activities, Discontinued Operations

113,150

1,103,577

Net Cash Provided by (Used in) Discontinued Operations

113,150

1,106,277

Effect of exchange rate changes on cash

1,178

(101)

(1,902)

Cash and Cash Equivalents, at Carrying Value, Including Discontinued Operations Period Start

567,599

178,810

175,620

^[3]

Cash and Cash Equivalents, at Carrying Value, Including Discontinued Operations Period End

$ 314,094

$ 567,599

$ 178,810

[1]	Inclusive of $33.8 million related to the write off of deferred financing costs
[2]	Inclusive of $4.2 million related to the write off of deferred financing costs, premiums and discounts.
[3]	Inclusive of cash and cash equivalents included in discontinued operations.

Consolidated Statement of Convertible Preferred Stock and Equity - USD ($)

Total

4.50% Mandatory Convertible Preferred Stock [Member]

Common Stock [Member]

Additional Paid-in Capital

Foreign Currency Translation Adjustments

Derivative Instruments

Dividends/Distributions in Excess of Earnings

Noncontrolling Interest

AOCI Attributable to Parent [Member]

6.875% Mandatory Convertible Preferred Stock [Member]

Preferred Stock [Member]

6.875% Mandatory Convertible Preferred Stock [Member]

Additional Paid-in Capital

Common Stock [Member]

Additional Paid-in Capital

4.50% Mandatory Convertible Preferred Stock [Member]

Preferred Stock [Member]

Discontinued Operations, Disposed of by Sale [Member]

Discontinued Operations [Member]

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Accumulated other Comprehensive Income (Loss), Net of Tax

9,775,000

$ 15,820,000

Balance, value at Dec. 31, 2014

6,737,228,000

$ 3,339,000

$ 9,512,396,000

$ 34,545,000

$ (18,725,000)

$ (2,815,428,000)

$ 21,003,000

$ 0

$ 98,000

Balance, (in shares) at Dec. 31, 2014

333,856,632

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Stock-based compensation related activity, net of forfeitures, value

65,840,000

$ 2,000

65,838,000

Stock-based compensation related activity, net of forfeitures, shares

251,554

Purchases and retirement of capital stock, value

(29,657,000)

$ (3,000)

(29,654,000)

Purchases and retirement of capital stock, shares

(336,526)

Other Comprehensive Income (Loss), Net of Tax

^[1]

(21,090,000)

(38,943,000)

18,725,000

(872,000)

$ (20,218,000)

Derivative instruments reclassified into results of operations, net of tax

18,725,000

Noncontrolling Interest, Period Increase (Decrease)

$ (23,474,000)

Common stock dividends/distributions

(1,119,973,000)

Dividends, Preferred Stock

(43,988,000)

Preferred stock dividends

(43,988,000)

Balance, value at Dec. 31, 2015

1,524,335,000

1,520,992,000

3,343,000

7,089,221,000

$ 3,338,000

9,548,580,000

(4,398,000)

(2,458,397,000)

$ 0

$ 98,000

Balance, (in shares) at Dec. 31, 2015

333,771,660

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Accumulated other Comprehensive Income (Loss), Net of Tax

9,775,000

(4,398,000)

Stock-based compensation related activity, net of forfeitures, value

86,273,000

$ 2,000

86,271,000

Stock-based compensation related activity, net of forfeitures, shares

263,782

Purchases and retirement of capital stock, value

(24,936,000)

$ (3,000)

(24,933,000)

Purchases and retirement of capital stock, shares

(289,531)

Conversion of redeemable preferred stock into Common Stock, shares

11,612,684

Stock Issued During Period, Value, Conversion of Convertible Securities

$ 116,000

Conversion of Stock, Shares Converted

(9,775,000)

Conversion of Stock, Amount Converted

$ (98,000)

Stock Issued During Period, Shares, New Issues

15,178,064

Other Comprehensive Income (Loss), Net of Tax

1,325,865,000

$ 152,000

1,325,713,000

(1,490,000)

^[1]

(1,490,000)

^[1]

(1,490,000)

^[1]

Proceeds and Excess Tax Benefit from Share-based Compensation

2,623,000

$ 2,623,000

Other Adjustments to Additional Paid in Capital | Conversion of Preferred Stock [Member]

(18,000)

Noncontrolling Interest, Increase from Business Combination

Derivative instruments reclassified into results of operations, net of tax

Common stock dividends/distributions

(1,244,423,000)

Dividends, Preferred Stock

(32,991,000)

Balance, value at Dec. 31, 2016

356,973,000

$ 7,557,115,000

$ 3,605,000

10,938,236,000

(5,888,000)

(3,378,838,000)

$ 0

Balance, (in shares) at Dec. 31, 2016

360,536,659

360,536,659.000

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Accumulated other Comprehensive Income (Loss), Net of Tax

$ (5,888,000)

Stock-based compensation related activity, net of forfeitures, value

99,988,000

$ 10,000

99,978,000

Stock-based compensation related activity, net of forfeitures, shares

861,028

Purchases and retirement of capital stock, value

(23,307,000)

$ (3,000)

(23,304,000)

Purchases and retirement of capital stock, shares

(259,331)

Conversion of redeemable preferred stock into Common Stock, shares

Stock Issued During Period, Value, Conversion of Convertible Securities

$ 0

Conversion of Stock, Shares Converted

(2,000)

Stock Issued During Period, Shares, New Issues

45,142,300

1,650,000,000

Net Proceeds from Issuances of Stock, Value

$ 451,000

$ 17,000

$ 1,607,759,000

$ 1,607,742,000

$ 4,221,329,000

$ 4,220,878,000

Other Comprehensive Income (Loss), Net of Tax

^[1]

1,899,000

$ 1,899,000

Other Adjustments to Additional Paid in Capital | Recognition of Excess Tax Benefits

77,000

Other Adjustments to Additional Paid in Capital | Conversion of Preferred Stock [Member]

Derivative instruments reclassified into results of operations, net of tax

Common stock dividends/distributions

(1,512,034,000)

Dividends, Preferred Stock

(58,294,000)

Balance, value at Dec. 31, 2017

444,550,000

$ 12,339,082,000

$ 4,063,000

$ 16,843,607,000

$ (3,989,000)

$ 0

$ (4,504,616,000)

$ 0

$ 17,000

$ 0

Balance, (in shares) at Dec. 31, 2017

406,280,673

406,280,673.000

Increase (Decrease) in Stockholders' Equity [Roll Forward]

Accumulated other Comprehensive Income (Loss), Net of Tax

1,649,998

1,649,998,000

$ (3,989,000)

[1]	See the consolidated statement of operations and comprehensive income (loss) for the components of "total other comprehensive income (loss)" and note 9 with respect to the reclassification adjustment.

Basis of Presentation

12 Months Ended

Dec. 31, 2017

Basis of Presentation [Abstract]

Basis of Presentation


	Basis of Presentation

The consolidated financial statements include the accounts of Crown Castle International Corp. and its predecessor, as applicable (together, "CCIC"), and their subsidiaries, collectively referred to herein as the "Company." All significant intercompany balances and transactions have been eliminated in consolidation. As used herein, the term "including," and any variation thereof, means "including without limitation." The use of the word "or" herein is not exclusive. Unless the context suggests otherwise, references to "U.S." are to the United States of America and Puerto Rico, collectively.

The Company owns, operates and leases shared communications infrastructure that is geographically dispersed throughout the U.S, including (1) towers and other structures, such as rooftops (collectively, "towers"), and (2) fiber primarily supporting small cell networks ("small cells") and fiber solutions. The Company's towers, fiber and small cells assets are collectively referred to herein as "communications infrastructure," and the Company's customers on its communications infrastructure are referred to herein as "tenants."

The Company's core business is providing access, including space or capacity, to its shared communications infrastructure via long-term contracts in various forms, including licenses, subleases and lease agreements (collectively, "contracts").

Approximately 53% of the Company's towers are leased or subleased or operated and managed under master leases, subleases, or other agreements with AT&T, Sprint, and T-Mobile. The Company has the option to purchase these towers at the end of their respective lease terms. The Company has no obligation to exercise such purchase options. Additional information concerning these towers is as follows:

◦

Approximately 22% of the Company's towers are leased or subleased or operated and managed under a master prepaid lease or other related agreements with AT&T for a weighted-average initial term of approximately 28 years, weighted on site rental gross margin. The Company has the option to purchase the leased and subleased towers from AT&T at the end of the respective lease or sublease terms for aggregate option payments of approximately $4.2 billion, which payments, if exercised, would be due between 2032 and 2048.


◦	Approximately 16% of the Company's towers are leased or subleased or operated and managed for an initial period of 32 years (through May 2037) under master leases, subleases, or other agreements with Sprint. The Company has the option to purchase in 2037 all (but not less than all) of the leased and subleased Sprint towers from Sprint for approximately $2.3 billion.

◦

Approximately 15% of the Company's towers are leased or subleased or operated and managed under a master prepaid lease or other related agreements with T-Mobile for a weighted-average initial term of approximately 28 years, weighted on site rental gross margin. The Company has the option to purchase the leased and subleased towers from T-Mobile at the end of the respective lease or sublease terms for aggregate option payments of approximately $2.0 billion, which payments, if exercised would be due between 2035 and 2049. In addition, through the acquisition of the rights to approximately 7,100 towers ("T-Mobile Acquisition"), there are another approximately 1% of the Company's towers subject to a lease and sublease or other related arrangements with AT&T. The Company has the option to purchase these towers that it does not otherwise already own at the end of their respective lease terms for aggregate option payments of up to approximately $405 million, which payments, if exercised, would be due between 2018 and 2032 (less than $10 million would be due before 2025).

As part of the Company's effort to provide comprehensive communications infrastructure solutions, the Company also offers certain network services relating to its communications infrastructure, consisting of (1) site development services primarily relating to existing or new tenant equipment installations on its towers and small cells, including: site acquisition, architectural and engineering, or zoning and permitting (collectively, "site development services") and (2) tenant equipment installation or subsequent augmentations (collectively, "installation services").

The Company operates as a real estate investment trust ("REIT") for U.S. federal income tax purposes. In addition, the Company has certain taxable REIT subsidiaries ("TRSs"). See note 11.

The preparation of financial statements in conformity with U.S. generally accepted accounting principles ("GAAP") requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

As a result of the 2017 Acquisitions of fiber assets as described in note 4, the Company has changed the name of the "Small Cells" operating segment to "Fiber." The Company changed the name of this segment to reflect its strategy of utilizing the same fiber assets to provide both small cells and fiber solutions to its customers. The name change did not impact the composition or the previously-reported operating results of the Fiber segment. As such, the Company's operating segments are now referred to as "Towers" and "Fiber." See note 16.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Summary of Significant Accounting Policies


	Summary of Significant Accounting Policies

Restricted Cash

Restricted cash represents (1) the cash held in reserve by the indenture trustees pursuant to the indenture governing certain of the Company's debt instruments, (2) cash securing performance obligations such as letters of credit, as well as (3) any other cash whose use is limited by contractual provisions. The restriction of rental cash receipts is a critical feature of certain of the Company's debt instruments, due to the applicable indenture trustee's ability to utilize the restricted cash for the payment of (1) debt service costs, (2) ground rents, (3) real estate or personal property taxes, (4) insurance premiums related to towers, (5) other assessments by governmental authorities and potential environmental remediation costs, or (6) a portion of advance rents from tenants. The restricted cash in excess of required reserve balances is subsequently released to the Company in accordance with the terms of the indentures. The Company has classified the increases and decreases in restricted cash as (1) cash provided by financing activities for cash held by indenture trustees based on consideration of the terms of the related indebtedness, although the cash flows have aspects of both financing activities and operating activities, (2) cash provided by investing activities for cash securing performance obligations and restricted cash that is acquired in acquisitions, or (3) cash provided by operating activities for the other remaining restricted cash.

The following table is a summary of the impact of restricted cash on the statement of cash flows.



	For the years ended December 31,
	2017			2016			2015
Net cash provided by (used from) operating activities	$	847		$	(4,547	)	$	3,974
Net cash provided by (used from) investing activities	$	(26	)	$	10,541		$	(3,752	)
Net cash provided by (used from) financing activities	$	3,808		$	(7,931	)	$	16,458

Receivables Allowance

An allowance for doubtful accounts is recorded as an offset to accounts receivable. The Company uses judgment in estimating this allowance and considers historical collections, current credit status, or contractual provisions. Additions to the allowance for doubtful accounts are charged either to "site rental costs of operations" or to "network services and other costs of operations," as appropriate; and deductions from the allowance are recorded when specific accounts receivable are written off as uncollectible.

Lease Accounting

General. The Company classifies its leases at inception as either operating leases or capital leases. A lease is classified as a capital lease if at least one of the following criteria is met, subject to certain exceptions noted below: (1) the lease transfers ownership of the leased assets to the lessee, (2) there is a bargain purchase option, (3) the lease term is equal to 75% or more of the economic life of the leased assets, or (4) the present value of the minimum lease payments equals or exceeds 90% of the fair value of the leased assets.

Lessee. Leases for land are evaluated for capital lease treatment if at least one of the first two criteria mentioned in the immediately preceding paragraph is present relating to the leased assets. When the Company, as lessee, classifies a lease as a capital lease, it records an asset in an amount equal to the present value of the minimum lease payments under the lease at the beginning of the lease term. Applicable operating leases are recognized on a straight-line basis as discussed under "costs of operations" below.

Lessor. If the Company is the lessor of leased property that is part of a larger whole (including a portion of space on a tower) and for which fair value is not objectively determinable, then such a lease is accounted for as an operating lease. As applicable, operating leases are recognized on a straight-line basis as discussed under "Revenue Recognition."

See also "Recent Accounting Pronouncements Not Yet Adopted" below for further discussion.

Property and Equipment

Property and equipment is stated at cost, net of accumulated depreciation. Property and equipment includes land owned in fee and perpetual easements for land, which have no definite life. When the Company purchases fee ownership or perpetual easements for the land previously subject to ground lease, the Company reduces the value recorded as land by the amount of any associated deferred ground lease payable or unamortized above-market leases. Depreciation is computed utilizing the straight-line method at rates based upon the estimated useful lives of the various classes of assets. Depreciation of communications infrastructure is computed with a useful life equal to the shorter of 20 years or the term of the underlying ground lease (including optional renewal periods). Additions, renewals, and improvements are capitalized, while maintenance and repairs are expensed. Labor and interest costs incurred directly related to the construction of certain property and equipment are capitalized during the construction phase of projects. For the years ended December 31, 2017, 2016, and 2015, the Company had $91.9 million, $86.1 million, and $36.7 million in capitalized labor costs, respectively. The carrying value of property and equipment is reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable.

Abandonments and write-offs of property and equipment are recorded to "asset write-down charges" on the Company's consolidated statement of operations and comprehensive income (loss) and were $14.3 million, $26.9 million, and $27.0 million for the years ended December 31, 2017, 2016, and 2015, respectively.

Asset Retirement Obligations

Pursuant to its ground lease, easement and leased facility agreements, the Company records obligations to perform asset retirement activities, including requirements to remove communications infrastructure or remediate the space upon which the Company's communications infrastructure resides. Asset retirement obligations are included in "other long-term liabilities" on the Company's consolidated balance sheet. The liability accretes as a result of the passage of time and the related accretion expense is included in "depreciation, amortization and accretion" on the Company's consolidated statement of operations and comprehensive income (loss). The associated asset retirement costs are capitalized as an additional carrying amount of the related long-lived asset and depreciated over the useful life of such asset.

Goodwill

Goodwill represents the excess of the purchase price for an acquired business over the allocated value of the related net assets. The Company tests goodwill for impairment on an annual basis, regardless of whether adverse events or changes in circumstances have occurred. The annual test begins with goodwill and all intangible assets being allocated to applicable reporting units. The Company's reporting units are the same as its operating segments (Towers and Fiber). The Company then performs a qualitative assessment to determine whether it is "more likely than not" that the fair value of the reporting units is less than its carrying amount. If it is concluded that it is "more likely than not" that the fair value of a reporting unit is less than its carrying amount, it is necessary to perform the two-step goodwill impairment test. The two-step goodwill impairment test begins with a comparison of the estimated fair value of the reporting unit and the carrying value of the reporting unit. The first step, commonly referred to as a "step-one impairment test," is a screen for potential impairment while the second step measures the amount of impairment if there is an indication from the first step that one exists. The Company's measurement of the fair value for goodwill is based on an estimate of discounted expected future cash flows of the reporting unit. The Company performed its most recent annual goodwill impairment test as of October 1, 2017, which resulted in no impairments.

Intangible Assets

Intangible assets are included in "site rental contracts and customer relationships, net" and "other intangible assets, net" on the Company's consolidated balance sheet and predominately consist of the estimated fair value of the following items recorded in conjunction with acquisitions: (1) site rental contracts and customer relationships, (2) below-market leases for land interest under the acquired communications infrastructure, or (3) other contractual rights such as trademarks. The site rental contracts and customer relationships intangible assets are comprised of (1) the current term of the existing leases, (2) the expected exercise of the renewal provisions contained within the existing leases, which automatically occur under contractual provisions, or (3) any associated relationships that are expected to generate value following the expiration of all renewal periods under existing leases.

The useful lives of intangible assets are estimated based on the period over which the intangible asset is expected to benefit the Company and gives consideration to the expected useful life of other assets to which the useful life may relate. Amortization expense for intangible assets is computed using the straight-line method over the estimated useful life of each of the intangible assets. The useful life of the site rental contracts and customer relationships intangible asset is limited by the maximum depreciable life of the communications infrastructure (20 years), as a result of the interdependency of the communications infrastructure and site rental leases. In contrast, the site rental contracts and customer relationships are estimated to provide economic benefits for several decades because of the low rate of tenant cancellations and high rate of renewals experienced to date. Thus, while site rental contracts and customer relationships are valued based upon the fair value, which includes assumptions regarding both (1) tenants' exercise of optional renewals contained in the acquired leases and (2) renewals of the acquired leases past the contractual term including exercisable options, the site rental contracts and customer relationships are amortized over a period not to exceed 20 years as a result of the useful life being limited by the depreciable life of the communications infrastructure.

The carrying value of other intangible assets with finite useful lives will be reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. The Company has a dual grouping policy for purposes of determining the unit of account for testing impairment of the site rental contracts and customer relationships intangible assets. First, the Company pools the site rental contracts and customer relationships with the related communications infrastructure assets into portfolio groups for purposes of determining the unit of account for impairment testing. Second and separately, the Company evaluates the site rental contracts and customer relationships by significant tenant or by tenant grouping for individually insignificant tenants, as appropriate. If the sum of the estimated future cash flows (undiscounted) expected to result from the use or eventual disposition of an asset is less than the carrying amount of the asset, an impairment loss is recognized. Measurement of an impairment loss is based on the fair value of the asset.

Deferred Credits

Deferred credits are included in "deferred revenues" and "other long-term liabilities" on the Company's consolidated balance sheet and consist of the estimated fair value of the following items recorded in conjunction with acquisitions: (1) below-market tenant leases for contractual interests with tenants on acquired communications infrastructure, which are amortized to site rental revenues and (2) above-market leases for land interests under the Company's communications infrastructure, which are amortized to site rental cost of operations.

Fair value for these deferred credits represents the difference between (1) the stated contractual payments to be made pursuant to the in-place lease and (2) management's estimate of fair market lease rates for each corresponding lease. Deferred credits are measured over a period equal to the estimated remaining economic lease term considering renewal provisions or economics associated with those renewal provisions, to the extent applicable. Deferred credits are amortized over their respected estimated lease terms at the time of acquisition.

Deferred Financing Costs

Third-party costs incurred to obtain financing, with the exception of costs incurred related to revolving lines of credit, are deferred and are included as a direct deduction from the carrying amount of the related debt liability in "debt and other long-term obligations" on the Company's consolidated balance sheet. Third party costs incurred to obtain financing through a revolving line of credit are deferred and are included in "long-term prepaid rent and other assets, net" on the Company's consolidated balance sheet.

Revenue Recognition

Site rental revenues are recognized on a monthly basis over the fixed, non-cancelable term of the relevant contract (generally ranging from five to 15 years for site rental revenues derived from wireless customers and three to 20 years for site rental revenues derived from the Company's fiber solutions business (including from organizations with high-bandwidth and multi-location demands)), regardless of whether the payments from the tenant are received in equal monthly amounts. Certain of the Company's contracts contain fixed escalation clauses (such as fixed dollar or fixed percentage increases) or inflation-based escalation clauses (such as those tied to the consumer price index ("CPI")). If the payment terms call for fixed escalations, upfront payments, or rent free periods, the revenue is recognized on a straight-line basis over the fixed, non-cancelable term of the agreement. When calculating straight-line rental revenues, the Company considers all fixed elements of tenant contractual escalation provisions, even if such escalation provisions contain a variable element in addition to a minimum. The Company's assets related to straight-line site rental revenues include current amounts of $86.0 million and $67.2 million included in "other current assets" and non-current amounts of $1.3 billion and $1.3 billion included in "deferred site rental receivables" for the years ended December 31, 2017 and 2016, respectively. Amounts billed or received prior to being earned are deferred and reflected in "deferred revenues" and "other long-term liabilities."

Network services revenues are recognized after completion of the applicable service. Nearly all of the installation services are billed on a cost-plus profit basis and site development services are billed on a fixed fee basis.

In jurisdictions where the Company determines that it is the principal taxpayer, taxes and surcharges are recorded on a gross basis. In jurisdictions where the Company determines that it is acting as a collection agent for the government authority (for example, in collecting sales taxes or value-added taxes collected from customers), such amounts are presented on a net basis.

See also "Recent Accounting Pronouncements Not Yet Adopted" below for further discussion.

Costs of Operations

Approximately 55% of the Company's site rental costs of operations expenses consist of Towers ground lease expenses, and the remainder includes fiber access expenses, property taxes, repairs and maintenance expenses, employee compensation or related benefit costs, or utilities. Generally, the ground leases for land are specific to each site and are for an initial term of five years and are renewable for pre-determined periods. The Company also enters into term easements and ground leases in which it prepays the entire term in advance. Fiber access expenses primarily consist of leases of fiber assets and other access agreements to facilitate the Company's communications infrastructure.

Ground lease and fiber access expenses are recognized on a monthly basis, regardless of whether the payment terms require the Company to make payments annually, quarterly, monthly, or for the entire term in advance. Certain of the Company's ground lease and fiber access agreements contain fixed escalation clauses (such as fixed dollar or fixed percentage increases) or inflation-based escalation clauses (such as those tied to the CPI). If the payment terms include fixed escalation provisions, the effect of such increases is recognized on a straight-line basis. The Company calculates the straight-line expense using a time period that equals or exceeds the remaining depreciable life of the communications infrastructure asset. Further, when a tenant has exercisable renewal options that would compel the Company to exercise existing renewal options, the Company has straight-lined the expense over a sufficient portion of such renewals to coincide with the final termination of the tenant's renewal options. The Company's non-current liability related to straight-line expense is included in "other long-term liabilities" on the Company's consolidated balance sheet. The Company's assets related to prepaid agreements is included in "prepaid expenses" and "long-term prepaid rent and other assets, net" on the Company's consolidated balance sheet.

Network services and other costs of operations predominately consist of third-party service providers such as contractors and professional services firms and, to a lesser extent, internal labor costs.

Acquisition and Integration Costs

All direct or incremental costs related to a business combination are expensed as incurred. Costs include severance, retention bonuses payable to employees of an acquired enterprise, temporary employees to assist with the integration of the acquired operations, or fees paid for services such as consulting, accounting, legal, or engineering reviews. These business combination costs are included in "acquisition and integration costs" on the Company's consolidated statement of operations and comprehensive income (loss). See note 4 for a discussion of the Company's recent acquisitions.

Stock-Based Compensation

Restricted Stock Units. The Company records stock-based compensation expense only for those unvested restricted stock units ("RSUs") for which the requisite service is expected to be rendered. The cumulative effect of a change in the estimated number of RSUs for which the requisite service is expected to be or has been rendered is recognized in the period of the change in the estimate. To the extent that the requisite service is rendered, compensation cost for accounting purposes is not reversed; rather, it is recognized regardless of whether or not the awards vest. A discussion of the Company's valuation techniques and related assumptions and estimates used to measure the Company's stock-based compensation is as follows:

Valuation. The fair value of RSUs without market conditions is determined based on the number of shares relating to such RSUs and the quoted price of the Company's common stock at the date of grant. The Company estimates the fair value of RSUs with market conditions granted using a Monte Carlo simulation. The Company's determination of the fair value of RSUs with market conditions on the date of grant is affected by its common stock price as well as assumptions regarding a number of highly complex or subjective variables. The determination of fair value using a Monte Carlo simulation requires the input of subjective assumptions, and other reasonable assumptions could provide differing results.

Amortization Method. The Company amortizes the fair value of all RSUs on a straight-line basis for each separately vesting tranche of the award (graded vesting schedule) over the requisite service periods.

Expected Volatility. The Company estimates the volatility of its common stock at the date of grant based on the historical volatility of its common stock.

Expected Dividend Rate. The expected dividend rate at the date of grant is based on the then-current dividend yield.

Risk-Free Rate. The Company bases the risk-free rate on the implied yield currently available on U.S. Treasury issues with an equivalent remaining term equal to the expected life of the award.

Forfeitures. The Company uses historical data and management's judgment about the future employee turnover rates to estimate the number of shares for which the requisite service period will not be rendered.

Interest Expense and Amortization of Deferred Financing Costs

The components of interest expense and amortization of deferred financing costs are as follows:



	Years Ended December 31,
	2017			2016			2015
Interest expense on debt obligations	$	581,314		$	500,699		$	490,002
Amortization of deferred financing costs and adjustments on long-term debt, net	19,035			19,087			21,048
Amortization of interest rate swaps	—			—			18,725
Capitalized interest	(11,545		)	(7,010		)	(4,805		)
Other	1,878			2,256			2,158
Total	$	590,682		$	515,032		$	527,128

The Company amortizes deferred financing costs, discounts, premiums, and purchase price adjustments on long-term debt over the estimated term of the related borrowing using the effective interest yield method. Discounts or purchase price adjustments are generally presented as a direct reduction to the related debt obligation on the Company's consolidated balance sheet.

Income Taxes

The Company operates as a REIT for U.S. federal income tax purposes. As a REIT, the Company is generally entitled to a deduction for dividends that it pays and therefore is not subject to U.S. federal corporate income tax on its taxable income that is currently distributed to its stockholders. The Company also may be subject to certain federal, state, local, and foreign taxes on its income and assets, including (1) alternative minimum taxes (repealed effective January 1, 2018), (2) taxes on any undistributed income, (3) taxes related to the TRSs, (4) franchise taxes, (5) property taxes, and (6) transfer taxes. In addition, the Company could in certain circumstances be required to pay an excise or penalty tax, which could be significant in amount, in order to utilize one or more relief provisions under the Internal Revenue Code of 1986, as amended ("Code"), to maintain qualification for taxation as a REIT.

During the fourth quarter of 2015, the Company completed the necessary steps to include small cells that were previously included in one or more wholly-owned TRSs in the REIT effective January 2016. As a result, during the fourth quarter of 2015, the Company de-recognized the related net deferred tax liabilities. Effective January 4, 2016, the Company's small cells that were previously included in one or more TRSs were included in the REIT. See note 11.

Additionally, the Company has included in TRSs certain other assets and operations. Those TRS assets and operations will continue to be subject, as applicable, to federal and state corporate income taxes or to foreign taxes in the jurisdictions in which such assets and operations are located. The Company's foreign assets and operations (including its tower operations in Puerto Rico) most likely will be subject to foreign income taxes in the jurisdictions in which such assets and operations are located, regardless of whether they are included in a TRS or not. The Company will be subject to a federal corporate level tax rate (currently 21%) on the gain recognized from the sale of assets occurring within a specified period (generally 5 years) after the REIT conversion up to the amount of the built in gain that existed on January 1, 2014, which is based upon the fair market value of those assets in excess of the Company's tax basis on January 1, 2014. This gain can be offset by any remaining federal net operating loss carryforwards ("NOLs").

For the Company's TRSs, the Company accounts for income taxes using an asset and liability approach, which requires the recognition of deferred income tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company's financial statements or tax returns. Deferred income tax assets and liabilities are determined based on the temporary differences between the financial statement and tax bases of assets and liabilities using enacted tax rates. A valuation allowance is provided on deferred tax assets if it is determined that it is "more likely than not" that the asset will not be realized. The Company records a valuation allowance against deferred tax assets when it is "more likely than not" that some portion or all of the deferred tax asset will not be realized. The Company reviews the recoverability of deferred tax assets each quarter and based upon projections of future taxable income, reversing deferred tax liabilities or other known events that are expected to affect future taxable income, records a valuation allowance for assets that do not meet the "more likely than not" realization threshold. Valuation allowances may be reversed if related deferred tax assets are deemed realizable based upon changes in facts and circumstances that impact the recoverability of the asset.

The Company recognizes a tax position if it is "more likely than not" that it will be sustained upon examination. The tax position is measured at the largest amount that is greater than 50 percent likely of being realized upon ultimate settlement. The Company reports penalties and tax-related interest expense as a component of the benefit (provision) for income taxes. As of December 31, 2017 and 2016, the Company has not recorded any penalties related to its income tax positions.

See note 11.

Per Share Information

Basic net income (loss) attributable to CCIC common stockholders, per common share excludes dilution and is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period. For the year ended December 31, 2017, diluted net income (loss) attributable to CCIC common stockholders, per common share is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period plus any potential dilutive common share equivalents, including shares issuable upon (1) the vesting of RSUs as determined under the treasury stock method and (2) conversion of the Company's 6.875% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share ("6.875% Convertible Preferred Stock"), as determined under the if-converted method. For the years ended December 31, 2016 and December 31, 2015, diluted income (loss) attributable to CCIC common stockholders, per common share is computed by dividing net income (loss) attributable to CCIC common stockholders by the weighted-average number of common shares outstanding during the period plus any potential dilutive common share equivalents, including shares issuable upon (1) the vesting of RSUs as determined under the treasury stock method and (2) conversion of the Company's then outstanding 4.50% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share ("4.50% Convertible Preferred Stock"), as determined under the if-converted method.

A reconciliation of the numerators and denominators of the basic and diluted per share computations is as follows:



	Years Ended December 31,
	2017			2016			2015
Net income (loss) from continuing operations	$	444,550		$	356,973		$	525,286
Dividends on preferred stock	(58,294		)	(32,991		)	(43,988		)
Net income (loss) from continuing operations attributable to CCIC common stockholders for basic and diluted computations	$	386,256		$	323,982		$	481,298

Income (loss) from discontinued operations, net of tax	—			—			999,049
Less: Net income (loss) attributable to the noncontrolling interest	—			—			3,343
Net income (loss) from discontinued operations attributable to CCIC common stockholders for basic and diluted computations	—			—			995,706

Weighted-average number of common shares outstanding (in thousands):
Basic weighted-average number of common stock outstanding	381,740			340,349			333,002
Effect of assumed dilution from potential common shares relating to RSUs	1,481			530			1,060
Diluted weighted-average number of common shares outstanding	383,221			340,879			334,062
Net income (loss) attributable to CCIC common stockholders, per common share:
Income (loss) from continuing operations, basic	$	1.01		$	0.95		$	1.45
Income (loss) from discontinued operations, basic	$	—		$	—		$	2.99
Net income (loss) attributable to CCIC common stockholders, basic	$	1.01		$	0.95		$	4.44
Income (loss) from continuing operations, diluted	$	1.01		$	0.95		$	1.44
Income (loss) from discontinued operations, diluted	$	—		$	—		$	2.98
Net income (loss) attributable to CCIC common stockholders, diluted	$	1.01		$	0.95		$	4.42

For the year ended December 31, 2017, 15.0 million common share equivalents related to the 6.875% Convertible Preferred Stock were excluded from the dilutive common shares because the impact of the conversion of such preferred stock would be anti-dilutive based on the Company's common stock price as of December 31, 2017. For the year ended December 31, 2015, 11.4 million common share equivalents related to the then outstanding 4.50% Convertible Preferred Stock were excluded from the dilutive common shares because the impact of the conversion of such preferred stock would be anti-dilutive based on the Company's common stock price at the end of such year. See notes 12 and 13.

Fair Values

The Company's assets and liabilities recorded at fair value are categorized based upon a fair value hierarchy that ranks the quality and reliability of the information used to determine fair value. The three levels of the fair value hierarchy are (1) Level 1 — quoted prices (unadjusted) in active and accessible markets, (2) Level 2 — observable prices that are based on inputs not quoted in active markets but corroborated by market data, and (3) Level 3 — unobservable inputs and are not corroborated by market data. The Company evaluates fair value hierarchy level classifications quarterly, and transfers between levels are effective at the end of the quarterly period.

The fair value of cash and cash equivalents and restricted cash approximate the carrying value. The Company determines the fair value of its debt securities based on indicative quotes (that is non-binding quotes) from brokers that require judgment to interpret market information including implied credit spreads for similar borrowings on recent trades or bid/ask prices or quotes from active markets if applicable. Foreign currency swaps are valued at settlement amounts using observable exchange rates and, if material, reflect an adjustment for the Company's and contract counterparty's credit risk. There were no changes since December 31, 2016 in the Company's valuation techniques used to measure fair values. See note 10 for a further discussion of fair values.

Swaps

Interest Rate Swaps. The Company had previously entered into interest rate swaps to manage or reduce its interest rate risk, including the use of (1) forward-starting interest rate swaps to hedge its exposure to variability in future cash flows attributable to changes in LIBOR on anticipated financings, including refinancings and potential future borrowings or (2) interest rate swaps to hedge the interest rate variability on a portion of the Company's floating rate debt. Derivative financial instruments were entered into for periods that matched the related underlying exposures. The Company can elect whether or not to designate derivative financial instruments as accounting hedges. The Company can also enter into derivative financial instruments that are not designated as accounting hedges. As of December 31, 2017, the Company does not have any interest rate swaps.

Derivatives were recognized on the consolidated balance sheet at fair value. If the derivative was designated as a cash flow hedge, the effective portion of the change in the fair value of the derivative was recorded as a separate component of stockholders' equity, captioned "accumulated other comprehensive income (loss)" on the Company's consolidated balance sheet, and recognized as increases or decreases to "interest expense and amortization of deferred financing costs" on the Company's consolidated statement of operations and comprehensive income (loss) when the hedged item affects earnings. If a hedge ceased to qualify for hedge accounting, any change in the fair value of the derivative since the date it ceased to qualify was recorded to "net gain (loss) on interest rate swaps." However, any amounts previously recorded to "accumulated other comprehensive income (loss)" would remain there until the original forecasted transaction affected earnings. In situations where it becomes probable that the hedged forecasted transaction will not occur, any gains or losses that have been recorded to "accumulated other comprehensive income (loss)" are immediately reclassified to earnings.

Foreign Currency Swaps. During 2015, the Company entered into foreign currency swaps to manage and reduce its foreign currency risk related to the May 2015 sale of the Company's formerly 77.6% owned subsidiary that operated towers in Australia ("CCAL") (see note 3). The derivatives were recognized on the consolidated balance sheet at fair value as of December 31, 2015. These swaps were not designated as accounting hedges and as such, the corresponding gain (loss) on the fair value adjustment is included as a component of "other income (expense)" on the Company's consolidated statement of operations and comprehensive income (loss). See note 9. In January 2016, the then outstanding swap related to the installment payment received from the Buyer (as defined in note 3) was cash settled.

Recently Adopted Accounting Pronouncements

No accounting pronouncements adopted during the year ended December 31, 2017 had a material impact on the Company's consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

In May 2014, the FASB released updated guidance regarding the recognition of revenue from contracts with customers, exclusive of those contracts within lease accounting. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (1) identify the contracts with the customer; (2) identify the performance obligations in the contract; (3) determine the contract price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when (or as) the entity satisfies a performance obligation. This guidance is effective for the Company on January 1, 2018, following the FASB's July 2015 decision to defer the effective date of the standard by one year. This guidance is required to be applied, at the Company's election, either (1) retrospectively to each prior reporting period presented, or (2) with the cumulative effect being recognized at the date of initial application. The Company will adopt the guidance effective January 1, 2018 with the cumulative effect being recognized at the date of initial application, and the adoption of this guidance will not have a material impact on its consolidated financial statements.

In February 2016, the FASB issued new guidance on the recognition, measurement, presentation and disclosure of leases. The new guidance requires lessees to recognize a right-of-use asset and a lease liability, initially measured at the present value of the lease payments for all leases with a term greater than 12 months. The accounting for lessors remains largely unchanged from existing guidance. This guidance is effective for the Company as of January 1, 2019 and is required to be applied using a modified retrospective approach for all leases existing at, or entered into after, the beginning of the earliest comparative period presented. Although early adoption is permitted, the Company does not expect to early adopt the new guidance prior to January 1, 2019. With regard to the application of this guidance to the Towers segment, the Company expects that (1) its Towers lessee arrangements will continue to be classified as operating leases under the new guidance; (2) this guidance will have a material impact on its consolidated balance sheet due to the addition of right-of-use assets and lease liabilities for all lessee arrangements with a term greater than 12 months; and (3) there will not be a material impact to its consolidated statement of operations and consolidated statement of cash flows. With regard to the application of this guidance to the Fiber segment, the Company (1) has established and is progressing through the various steps of a cross-functional project plan to assess the impact of the standard; (2) expects this guidance to have a material impact on its consolidated balance sheet due to the addition of right-of-use assets and lease liabilities for all lessee arrangements with a term greater than 12 months; and (3) continues to assess additional impacts to its consolidated financial statements, including the consolidated statement of operations and the consolidated statement of cash flows.

In November 2016, the FASB issued new guidance which requires an entity's statement of cash flows to explain the change in restricted cash and restricted cash equivalents in addition to cash and cash equivalents. This new guidance also requires an entity that includes cash, cash equivalents, restricted cash and restricted cash equivalents on multiple lines on its balance sheet to present a reconciliation between its statement of cash flows and its balance sheet. The guidance is effective for the Company on January 1, 2018, and is required to be applied retrospectively to each prior reporting period presented. The Company will adopt this guidance effective January 1, 2018, and believes that the impact of the new guidance will be limited to certain changes in presentation on the consolidated statement of cash flows.

In January 2017, the FASB issued new guidance which clarifies the definition of a business in order to assist companies in evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. The guidance is effective for the Company as of January 1, 2018, and is required to be applied prospectively. The Company will adopt this guidance effective January 1, 2018 and will apply the new guidance to prospective transactions. The adoption of this guidance will not have a material impact on the Company's consolidated financial statements.

In January 2017, the FASB issued new guidance to simplify the accounting for goodwill impairment by removing the second step of the existing goodwill impairment test. As a result of the guidance, goodwill impairment, if any, will be measured during the step-one impairment test as the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. Additionally, the guidance does not change the option to complete a qualitative assessment prior to performing a step-one impairment test. The guidance is effective for the Company as of January 1, 2020. Early adoption is permitted. The Company is currently evaluating the impact of the guidance, including the impact on its consolidated financial statements.

In February 2017, the FASB issued new guidance which clarifies the scope and application of accounting for the de-recognition of non-financial assets and in substance non-financial assets, including sales and partial sales of real estate assets. The new guidance also eliminates the existing industry specific guidance for partial sales of real estate and requires full gain recognition upon partial sales of real estate. The guidance is effective for the Company as of January 1, 2018. The Company will adopt this guidance effective January 1, 2018, and the adoption of this guidance will not have a material impact on its consolidated financial statements.

Discontinued Operations (Notes)

12 Months Ended

Dec. 31, 2017

Discontinued Operations [Abstract]

Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]

Discontinued Operations

On May 14, 2015, the Company entered into a definitive agreement to sell CCAL to a consortium of investors led by Macquarie Infrastructure and Real Assets (collectively, "Buyer"). On May 28, 2015, the Company completed the sale. At closing, the Company received net proceeds of approximately $1.1 billion after accounting for the Company's 77.6% ownership interest, repayment of intercompany debt owed to the Company by CCAL and estimated transaction fees and expenses, exclusive of the impact of foreign currency swaps related to the CCAL sale (see note 9).

As part of the sale of CCAL, in January 2016, the Company received an installment payment from the Buyer totaling approximately $124 million, inclusive of the impact of the related foreign currency swap (see note 9).

During the second quarter 2015, the Company used net proceeds from the sale of CCAL to repay portions of outstanding borrowings under the Company's then outstanding senior secured credit facility ("2012 Credit Facility"). See note 8.

The Company entered into foreign currency swaps to manage and reduce its foreign currency risk associated with the sale of CCAL. These swaps are not included in discontinued operations. See note 9.

Prior to the sale of CCAL, it had historically been a separate operating segment of the Company. The sale of CCAL is treated as discontinued operations for all periods presented pursuant to ASU 2014-08, which the Company adopted on January 1, 2015. The sale of CCAL represented a strategic shift of the Company to focus on its U.S. operations. The gain from disposal of CCAL is included in discontinued operations on the consolidated statement of operations. The tables below set forth the results of operations related to discontinued operations for the year ended December 31, 2015.



	Year Ended December 31,
	2015^(b)(c)
Total revenues	$	65,293
Total cost of operations^(a)	17,498
Depreciation, amortization and accretion	10,168
Total other expenses	10,481
Pre-tax income from discontinued operations	27,146
Benefit (provision) from income taxes	(7,456		)
Net income (loss) from discontinued operations^(d)	$	19,690


(a)	Exclusive of depreciation, amortization, and accretion shown separately.


(b)	No interest expense has been allocated to discontinued operations.


(c)	CCAL results are through May 28, 2015, which was the closing date of the Company's sale of CCAL.


(d)	Exclusive of the gain (loss) from disposal of discontinued operations, net of tax, as presented on the consolidated statement of operations.

The Company recorded a gain on the sale of CCAL during the year ended December 31, 2015, which was comprised of the following items:



Cash received from sale of CCAL^(a)	$	1,139,369
Installment payment receivable due January 2016^(a)	117,384
Total proceeds from sale of CCAL	$	1,256,753
Adjusted for:
Net assets and liabilities related to discontinued operations^(b)(c)	258,575
Transaction fees and expenses	23,059
Foreign currency translation reclassification adjustments^(d)	(25,678		)
Pre-tax gain (loss) from disposal of discontinued operations	1,000,797
Income taxes related to the sale of CCAL	(21,438		)
Gain (loss) from disposal of discontinued operations	$	979,359


(a)	Exclusive of foreign currency swaps and based on exchange rates as of May 28, 2015, which was the closing date of the Company's sale of CCAL. See note 9. The impact of fluctuations in the exchange rate subsequent to the closing date are reflected as a component of "other income (expense)" on the Company's consolidated statement of operations.


(b)	Represents net assets attributable to CCIC, net of the disposition of noncontrolling interest of $23.5 million.


(c)	Inclusive of $11.1 million of cash.


(d)	Represents foreign currency translation adjustments previously included in "accumulated other comprehensive income (loss)" on the consolidated balance sheet and reclassified to "net gain (loss) from disposal of discontinued operations, net of tax" on the consolidated statement of operations and comprehensive income (loss).

Acquisitions

12 Months Ended

Dec. 31, 2017

Acquisitions

Acquisitions

2015 Sunesys Acquisition

During April 2015, the Company entered into a definitive agreement to acquire Quanta Fiber Networks, Inc. ("Sunesys") for approximately $1.0 billion in cash, subject to certain limited adjustments ("Sunesys Acquisition"). On August 4, 2015, the Company closed the Sunesys Acquisition. The results of operations from Sunesys have been included in the Company's consolidated statement of operations since the date of acquisition.

Prior to the closing, Sunesys was a wholly owned subsidiary of Quanta Services, Inc. and a fiber services provider that owned or had rights to nearly 10,000 route miles of fiber in major metropolitan markets across the U.S., including Los Angeles, Philadelphia, Chicago, Atlanta, Silicon Valley, and northern New Jersey. Approximately 60% of Sunesys' fiber route miles were located in the top 10 basic trading areas.

The Company utilized borrowings under the 2012 Credit Facility and cash on hand to fund the cash consideration of approximately $1.0 billion. See note 8.

The final purchase price allocation for the Sunesys Acquisition is shown below.



Final Purchase Price Allocation
Current assets	$	15,306
Property and equipment	444,394
Goodwill^(a)	331,775
Other intangible assets, net	254,079
Current liabilities	(20,233		)
Other non-current liabilities	(37,356		)
Net assets acquired^(b)	$	987,965


(a)	The final purchase price allocation for the Sunesys Acquisition resulted in the recognition of goodwill based on the Company's expectation to leverage the Sunesys fiber footprint to support new small cells. The Sunesys fiber is complementary to the Company's existing fiber assets and is located where the Company expects to see wireless carrier network investments.


(b)	Assets acquired in the Sunesys Acquisition are included in the Company's REIT and as such, no deferred taxes were recorded in connection with the Sunesys Acquisition.

Net revenues and net income (loss) attributable to the Sunesys Acquisition are included in the Company's consolidated statements of operations and comprehensive income (loss), since the date the acquisition was completed. For the years ended December 31, 2017, 2016 and 2015, the Sunesys Acquisition contributed consolidated net revenues of $121.7 million, $112.6 million and $41.4 million, respectively.

2016 TDC Acquisition

In April 2016, the Company acquired Tower Development Corporation ("TDC"), a portfolio of approximately 330 towers, for approximately $461.0 million in cash ("TDC Acquisition"). The Company financed the acquisition with cash on hand, cash from borrowings under the Company's senior unsecured revolving credit facility ("2016 Revolver"), and cash from equity issuances under the ATM Program (see note 12). The final purchase price allocation was primarily comprised of customer relationships of approximately $140 million, property and equipment of approximately $107 million, and goodwill of approximately $211 million.

2017 FiberNet Acquisition

On November 1, 2016, the Company announced that it had entered into a definitive agreement to acquire FPL FiberNet Holdings, LLC and certain other subsidiaries of NextEra Energy, Inc. (collectively, "FiberNet") for approximately $1.5 billion in cash, subject to certain limited adjustments ("FiberNet Acquisition"). FiberNet is a fiber services provider in Florida and Texas that, as of the agreement date, owned or had rights to approximately 11,500 route miles of fiber installed or under construction, inclusive of approximately 6,000 route miles in top metro markets. On January 17, 2017, the Company closed the FiberNet Acquisition, which was financed using proceeds from its November 2016 Common Stock Offering (as defined in note 12) and borrowings under the 2016 Revolver (see note 8).

The preliminary purchase price allocation for the FiberNet Acquisition is shown below and is based upon a preliminary valuation which is subject to change as the Company obtains additional information with respect to fixed assets, intangible assets and certain liabilities.



Preliminary Purchase Price Allocation
Current assets	$	52,274
Property and equipment	438,478
Goodwill^(a)	777,563
Other intangible assets, net^(b)	327,338
Other non-current assets	2,449
Current liabilities	(41,120		)
Other non-current liabilities	(36,152		)
Net assets acquired^(c)	$	1,520,830


(a)	The preliminary purchase price allocation for the FiberNet Acquisition resulted in the recognition of goodwill based on:


•	the Company's expectation to leverage the FiberNet fiber footprint to support new small cells and fiber solutions,


•	the complementary nature of the FiberNet fiber to the Company's existing fiber assets and its location in top metro markets where the Company expects to see wireless carrier network investments,


•	the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and


•	other intangibles not qualified for separate recognition, including the assembled workforce.


(b)	Predominantly comprised of site rental contracts and customer relationships.


(c)	The vast majority of the assets will be included in the Company's REIT. As such, no deferred taxes were recorded in connection with the FiberNet Acquisition.

2017 Wilcon Acquisition

On April 17, 2017, the Company announced that it had entered into a definitive agreement to acquire Wilcon Holdings LLC ("Wilcon") from Pamlico Holdings and other unit holders of Wilcon for approximately $600 million in cash, subject to certain limited adjustments ("Wilcon Acquisition"). Wilcon is a fiber services provider that owns approximately 1,900 route miles of fiber, primarily in Los Angeles and San Diego. On June 26, 2017, the Company closed the Wilcon Acquisition, which was financed using proceeds from the May 2017 Common Stock Offering (as defined in note 12) and the 4.750% Senior Notes (as defined in note 8) offering.

The preliminary purchase price of approximately $600 million was primarily comprised of other intangible assets (predominantly comprised of site rental contracts and customer relationships) of approximately $140 million, property and equipment of approximately $150 million, goodwill of approximately $360 million, offset by deferred revenues of approximately $40 million.

The preliminary purchase price allocation for the Wilcon Acquisition resulted in the recognition of goodwill based on (1) the Company's expectation to leverage the Wilcon fiber footprint to support new small cells and fiber solutions, (2) the complementary nature of the Wilcon fiber to the Company's existing fiber assets and its location primarily in Los Angeles and San Diego, where the Company expects to see wireless carrier network investments, (3) the Company's belief that the acquired fiber assets are well positioned to benefit from the continued growth trends in the demand for data, and (4) other intangibles not qualified for separate recognition, including the assembled workforce. The preliminary purchase price allocation for the Wilcon Acquisition is based upon a preliminary valuation which is subject to change as the Company obtains additional information with respect to fixed assets, intangible assets and certain liabilities.

2017 Lightower Acquisition

On July 18, 2017, the Company announced that it had entered into a definitive agreement to acquire LTS Group Holdings LLC ("Lightower") from Berkshire Partners, Pamlico Capital and other investors for approximately $7.1 billion in cash, subject to certain limited adjustments ("Lightower Acquisition"). Lightower owns or has rights to approximately 32,000 route miles of fiber located primarily in top metro markets in the Northeast, including Boston, New York and Philadelphia. On November 1, 2017, the Company closed the Lightower Acquisition, which was financed using (1) cash on hand, including proceeds from the July 2017 Equity Offerings (as defined in note 12) and the August 2017 Senior Notes (as defined in note 8) offering, and (2) borrowings under the 2016 Revolver.

The preliminary purchase price allocation for the Lightower Acquisition is shown below and is based upon a preliminary valuation which is subject to change as the Company obtains additional information with respect to fixed assets, intangible assets and certain liabilities.



Preliminary Purchase Price Allocation
Current assets	$	104,643
Property and equipment	2,197,466
Goodwill^(a)	3,116,010
Other intangible assets, net^(b)	2,177,090
Other non-current assets	28,834
Current liabilities	(172,399		)
Other non-current liabilities	(299,667		)
Net assets acquired^(c)	$	7,151,977


(a)	The preliminary purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on:


•	the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions,


•	the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,


•	the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and


•	other intangibles not qualified for separate recognition, including the assembled workforce.


(b)	Predominantly comprised of site rental contracts and customer relationships.


(c)	The vast majority of the assets will be included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition.

Actual and Pro Forma Financial Information

Net revenues and net income (loss) attributable to acquisitions completed during the year ended December 31, 2017 are included in the Company's consolidated statements of operations and comprehensive income (loss), since the respective date each acquisition was completed. For the year ended December 31, 2017, the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition (collectively, "2017 Acquisitions") resulted in an increase to consolidated net revenues of $314.1 million.

The unaudited pro forma financial results for the years ended December 31, 2017 and 2016 combine the historical results of the Company, along with the historical results of the 2017 Acquisitions for the respective periods. The following table presents the unaudited pro forma consolidated results of operations of the Company as if each acquisition was completed as of January 1, 2016 for the periods presented below. The unaudited pro forma amounts are presented for illustrative purposes only and are not necessarily indicative of future consolidated results of operations.



	Twelve Months Ended December 31,
	2017				2016
Net revenues	$	5,050,166			$	4,864,852
Income (loss) before income taxes	541,389			^(b)(c)	367,326			^(b)(c)(d)
Benefit (provision) for income taxes	(28,960		)	^(a)	(20,968		)	^(a)
Net income (loss)	$	512,429		^(b)(c)	$	346,358		^(b)(c)(d)
Basic net income (loss) attributable to CCIC common stockholders, per common share	$	0.89		^(c)(e)	$	0.51		^(c)(e)
Diluted net income (loss) attributable to CCIC common stockholders, per common share	$	0.88		^(c)(e)	$	0.51		^(c)(e)

(a)

For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to the benefit (provision) for income tax as a result of the Company's REIT status. The vast majority of the assets and related income from the FiberNet Acquisition, the Wilcon Acquisition, and the Lightower Acquisition are included in the Company's REIT. The remaining assets are included in the Company's TRS. For purposes of the unaudited pro forma financial results, an adjustment has been made to reflect the additional tax impact of the income related to the TRS assets.


(b)	For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to depreciation and amortization of $247.1 million and $315.9 million, respectively, related to property and equipment and intangibles recorded as a result of the 2017 Acquisitions.


(c)	Pro forma amounts include the impact of the interest expense and common stock share issuances associated with the related debt and equity financings for the 2017 Acquisitions (see above and notes 8 and 12).


(d)	Amounts are inclusive of a total of $120 million of Lightower stock-based compensation expense and acquisition and integration costs.


(e)	Pro forma amounts include the impact of the preferred stock dividends related to the Mandatory Convertible Preferred Stock Offering (as defined in note 12) for the Lightower Acquisition (see above and note 12).

Property and Equipment

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and Equipment

The major classes of property and equipment are as follows:



	Estimated Useful Lives	As of December 31,
	Estimated Useful Lives	2017			2016
Land^(a)	—	$	1,859,431		$	1,747,335
Buildings	40 years	119,313			110,641
Communications infrastructure assets	1-20 years	17,183,482			13,825,394
Information technology assets and other	2-7 years	372,339			278,489
Construction in process	—	898,621			456,675
Total gross property and equipment		20,433,186			16,418,534
Less: accumulated depreciation		(7,500,301		)	(6,613,219		)
Total property and equipment, net		$	12,932,885		$	9,805,315


(a)	Includes land owned in fee and perpetual easements.

Depreciation expense for the years ended December 31, 2017, 2016 and 2015 was $914.9 million, $832.7 million and $774.9 million, respectively. Capital leases and associated leasehold improvements related to gross property and equipment, and accumulated depreciation was $4.3 billion and $1.7 billion, respectively, as of December 31, 2017. See notes 1 and 2, including discussion of the Company's prepaid master lease agreements.

Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets

Goodwill and Intangible Assets

Goodwill

The changes in the carrying value of goodwill for the years ended December 31, 2017 and December 31, 2016 were as follows:



Balance as of December 31, 2015	$	5,513,551
Additions due to TDC Acquisition^(a)	210,905
Adjustments due to other acquisitions, purchase price allocations and other, net	33,220
Balance as of December 31, 2016	$	5,757,676
Additions due to FiberNet Acquisition^(b)	777,563
Additions due to Wilcon Acquisition^(b)	357,606
Additions due to Lightower Acquisition^(b)	3,116,010
Adjustments due to other acquisitions, purchase price allocations and other, net	12,613
Balance as of December 31, 2017	$	10,021,468


(a)	The final purchase price allocation for the TDC Acquisition resulted in the recognition of goodwill in the Towers segment because of the anticipated growth opportunity in the acquired tower portfolio. See note 4.


(b)	The preliminary purchase price allocation for the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition resulted in the recognition of goodwill in the Fiber segment based on:


•	the Company's expectation to leverage the FiberNet, Wilcon and Lightower fiber footprint to support new small cell and fiber solutions,


•	the complementary nature of the FiberNet, Wilcon and Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,


•	the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and


•	other intangibles not qualified for separate recognition, including the assembled workforce. See note 4.

Intangibles

The following is a summary of the Company's intangible assets. See note 4 for further discussion of the Company's acquisitions.



	As of December 31, 2017							As of December 31, 2016
	Gross Carrying Value^(a)		Accumulated Amortization			Net Book Value		Gross Carrying Value		Accumulated Amortization			Net Book Value
Site rental contracts and customer relationships	$	7,782,934	$	(2,156,499	)	$	5,626,435	$	5,146,301	$	(1,847,523	)	$	3,298,778
Other intangible assets	502,891		(167,567		)	335,324		497,091		(145,797		)	351,294
Total	$	8,285,825	$	(2,324,066	)	$	5,961,759	$	5,643,392	$	(1,993,320	)	$	3,650,072


(a)	During the year ended December 31, 2017, intangible assets additions (primarily site rental contracts and customer relationships) from acquisitions had a weighted average amortization period of approximately 17 years.

Amortization expense related to intangible assets is classified as follows on the Company's consolidated statement of operations and comprehensive income (loss):



	For Years Ended December 31,
Classification	2017		2016		2015
Depreciation, amortization and accretion	$	314,447	$	264,656	$	251,443
Site rental costs of operations	18,373		19,367		20,420
Total amortization expense	$	332,820	$	284,023	$	271,863

The estimated annual amortization expense related to intangible assets (inclusive of those recorded as an increase to "site rental costs of operations") for the years ending December 31, 2018 to 2022 is as follows:



	Years Ending December 31,
	2018		2019		2020		2021		2022
Estimated annual amortization	$	445,849	$	444,889	$	444,589	$	444,155	$	443,688

Debt and Other Obligations [Abstract]

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Other Liabilities (Notes)

12 Months Ended

Dec. 31, 2017

Other Liabilities [Abstract]

Other Liabilities

Other long-term liabilities

The following is a summary of the components of "other long-term liabilities" as presented on the Company's consolidated balance sheet. See also note 2.



	December 31,
	2017		2016
Deferred rental revenues	$	1,076,845	$	983,263
Deferred ground lease payable	559,556		517,281
Above market leases for land interests, net	201,542		224,126
Deferred credits, net	531,856		207,992
Asset retirement obligation	173,733		146,100
Deferred income tax liabilities	5,192		8,075
Other long-term liabilities	5,313		392
Total	$	2,554,037	$	2,087,229

Pursuant to its ground lease, easement and leased facility agreements, the Company has the obligation to perform certain asset retirement activities, including requirements upon contract termination to remove communications infrastructure or remediate the space upon which its communications infrastructure resides. Accretion expense related to liabilities for retirement obligations amounted to $13.1 million, $11.3 million and $9.9 million for the years ended December 31, 2017, 2016, and 2015, respectively. As of December 31, 2017 and 2016, liabilities for retirement obligations were $173.7 million and $146.1 million, respectively, representing the net present value of the estimated expected future cash outlay. As of December 31, 2017, the estimated undiscounted future cash outlay for asset retirement obligations was approximately $1.2 billion. See note 2.

For the years ended December 31, 2017, 2016 and 2015, the Company recorded $19.3 million, $21.0 million and $22.5 million, respectively, as a decrease to "site rental costs of operations" for the amortization of above-market leases for land interests under the Company's towers. The estimated amortization expense related to above-market leases for land interests under the Company's towers recorded to site rental costs of operations for the years ending December 31, 2018 to 2022 is as follows:



	Years Ending December 31,
	2018		2019		2020		2021		2022
Above-market leases for land interests	$	18,277	$	17,674	$	16,769	$	15,667	$	14,580

For the years ended December 31, 2017, 2016 and 2015, the Company recognized $37.3 million, $33.6 million and $32.8 million, respectively, in "site rental revenues" related to the amortization of below market tenant leases. The following table summarizes the estimated annual amounts related to below-market tenant leases expected to be amortized into site rental revenues for the years ending December 31, 2018 to 2022 are as follows:



	Years Ending December 31,
	2018		2019		2020		2021		2022
Below-market tenant leases	$	65,104	$	59,145	$	53,050	$	49,745	$	44,910

Other accrued liabilities

Other accrued liabilities included accrued payroll and other accrued compensation of $141.0 million and $100.9 million, respectively, as of December 31, 2017 and 2016.

Debt and Other Obligations

12 Months Ended

Dec. 31, 2017

Debt and Other Obligations

See note 19 for a discussion of the Company's issuance of the January 2018 Senior Notes (as defined in note 19) and the application of the net proceeds therefrom.

The table below sets forth the Company's debt and other obligations as of December 31, 2017.



	Original Issue Date	Contractual Maturity Date		Outstanding Balance as of December 31,					Stated Interest Rate as of December 31,
	Original Issue Date	Contractual Maturity Date		2017			2016		2017		^(a)
Bank debt – variable rate:
2016 Revolver	Jan. 2016	Aug. 2022		$	980,000	^(b)	$	—	2.6	%	^(c)
2016 Term Loan A	Jan. 2016	Aug. 2022		2,396,588			1,954,173		2.6	%	^(c)
Total bank debt				3,376,588			1,954,173
Securitized debt – fixed rate:
Secured Notes, Series 2009-1, Class A-1	Jul. 2009	Aug. 2019	^(d)	31,813			51,416		6.3	%
Secured Notes, Series 2009-1, Class A-2	Jul. 2009	Aug. 2029	^(d)	69,500			68,737		9.0	%
Tower Revenue Notes, Series 2010-3	Jan. 2010	Jan. 2040	^(e)(f)	1,246,106			1,244,237		6.1	%
Tower Revenue Notes, Series 2010-6	Aug. 2010	Aug. 2040	^(e)(f)	995,354			993,557		4.9	%
Tower Revenue Notes, Series 2015-1	May 2015	May 2042	^(e)(f)	297,211			296,573		3.2	%
Tower Revenue Notes, Series 2015-2	May 2015	May 2045	^(e)(f)	692,325			691,285		3.7	%
Total securitized debt				3,332,309			3,345,805
Bonds – fixed rate:
5.250% Senior Notes	Oct. 2012	Jan. 2023		1,639,207			1,637,099		5.3	%
3.849% Secured Notes	Dec. 2012	Apr. 2023		992,663			991,279		3.8	%
4.875% Senior Notes	Apr. 2014	Apr. 2022		842,090			840,322		4.9	%
3.400% Senior Notes	Feb./May 2016	Feb. 2021		849,859			849,698		3.4	%
4.450% Senior Notes	Feb. 2016	Feb. 2026		891,145			890,118		4.5	%
3.700% Senior Notes	May 2016	June 2026		742,727			741,908		3.7	%
2.250% Senior Notes	Sept. 2016	Sept. 2021		695,383			693,893		2.3	%
4.000% Senior Notes	Feb. 2017	Mar. 2027		493,833			—		4.0	%
4.750% Senior Notes	May 2017	May 2047		343,209			—		4.8	%
3.200% Senior Notes	Aug. 2017	Sept. 2024		741,859			—		3.2	%
3.650% Senior Notes	Aug. 2017	Sept. 2027		990,965			—		3.7	%
Total bonds				9,222,940			6,644,317
Other:
Capital leases and other obligations	Various	Various	^(g)	227,783			226,847		Various
Total debt and other obligations				16,159,620			12,171,142
Less: current maturities and short-term debt and other current obligations				115,251			101,749
Non-current portion of long-term debt and other long-term obligations				$	16,044,369		$	12,069,393


(a)	Represents the weighted-average stated interest rate.


(b)	As of December 31, 2017, the undrawn availability under the 2016 Revolver was $2.5 billion. See note 19.


(c)	The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.125% to 2.000%, based on the Company's senior unsecured debt rating. The Company pays a commitment fee of approximately 0.200% per annum on the undrawn available amount under the 2016 Revolver.


(d)	The Secured Notes, Series 2009-1, Class A-1 and Secured Notes, Series 2009-1, Class A-2 are collectively referred to herein as "2009 Securitized Notes."


(e)	The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes") and Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes."

(f)

If the respective series of Tower Revenue Notes are not paid in full on or prior to an applicable anticipated repayment date, then Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes, and additional interest (of an additional approximately 5% per annum) will accrue on the respective Tower Revenue Notes. As of December 31, 2017, the Tower Revenue Notes have principal amounts of $2.3 billion, $300.0 million and $700.0 million, with anticipated repayment dates in 2020, 2022 and 2025, respectively. See note 19.


(g)	The Company's capital leases and other obligations relate to land, fiber, vehicles, and other assets and bear interest rates ranging up to 10% and mature in periods ranging from less than one year to approximately 30 years.

The credit agreement governing the Company's 2016 Credit Facility contains financial maintenance covenants. The Company is currently in compliance with these financial maintenance covenants, and based upon current expectations, the Company believes it will continue to comply with its financial maintenance covenants. In addition, certain of the Company's debt agreements also contain restrictive covenants that place restrictions on CCIC or its subsidiaries and may limit the Company's ability to, among other things, incur additional debt and liens, purchase the Company's securities, make capital expenditures, dispose of assets, undertake transactions with affiliates, make other investments, pay dividends or distribute excess cash flow.

Bank Debt

In January 2016, the Company completed the 2016 Credit Facility, which was originally comprised of (1) a $2.5 billion 2016 Revolver maturing in January 2021, (2) a $2.0 billion 2016 Term Loan A maturing in January 2021 and (3) a $1.0 billion senior unsecured 364-day revolving credit facility ("364-Day Facility") maturing in January 2017. The Company used the net proceeds from the 2016 Credit Facility (1) to repay the then outstanding 2012 Credit Facility and (2) for general corporate purposes. In February 2016, the Company used a portion of the net proceeds from the February 2016 Senior Notes (as defined below) offering to repay in full all outstanding borrowings under the then outstanding 364-Day Facility.

In February 2017, the Company entered into an amendment to the 2016 Credit Facility to (1) incur additional term loans in an aggregate principal amount of $500.0 million and (2) extend the maturity of both the 2016 Term Loan A and the 2016 Revolver to January 2022.

In August 2017, the Company entered into an amendment to the 2016 Credit Facility to (1) increase the commitments under the 2016 Revolver by $1.0 billion, for total commitments of $3.5 billion, and (2) extend the maturity of both the 2016 Term Loan A and the 2016 Revolver to August 2022.

Securitized Debt

The Tower Revenue Notes and the 2009 Securitized Notes (collectively, "Securitized Debt") are obligations of special purpose entities and their direct and indirect subsidiaries (each an "issuer"), all of which are wholly-owned, indirect subsidiaries of CCIC. The Tower Revenue Notes and 2009 Securitized Notes are governed by separate indentures. The January 2010 Tower Revenue Notes, August 2010 Tower Revenue Notes and May 2015 Tower Revenue Notes are governed by one indenture and consist of multiple series of notes, each with its own anticipated repayment date.

The net proceeds of the January 2010 Tower Revenue Notes and August 2010 Tower Revenue Notes were primarily used to repay the portion of the 2005 Tower Revenue Notes and 2006 Tower Revenue Notes not previously purchased. In April 2014, the Company utilized a portion of the net proceeds from the 4.875% Senior Notes (as defined below) offering to repay $300.0 million of the January 2010 Tower Revenue Notes which had an anticipated repayment date of January 2015.

The net proceeds of the May 2015 Tower Revenue Notes, together with proceeds received from the Company's sale of CCAL, were primarily used to (1) repay $250.0 million aggregate principal amount of August 2010 Tower Revenue Notes which had an anticipated repayment date of August 2015, (2) repay all of the then outstanding WCP Secured Wireless Site Contracts Revenue Notes, Series 2010-1 ("WCP Securitized Notes"), (3) repay portions of outstanding borrowings under the 2012 Credit Facility and (4) pay related fees and expenses.

The Securitized Debt is paid solely from the cash flows generated by the operation of the towers held directly and indirectly by the issuers of the respective Securitized Debt. The Securitized Debt is secured by, among other things, (1) a security interest in substantially all of the applicable issuers' assignable personal property, (2) a pledge of the equity interests in each applicable issuer and (3) a security interest in the applicable issuers' leases with tenants to lease tower space (space licenses). The governing instruments of two indirect subsidiaries ("Crown Atlantic" and "Crown GT") of the issuers of the Tower Revenue Notes generally prevent them from issuing debt and granting liens on their assets without the approval of a subsidiary of Verizon Communications. Consequently, while distributions paid by Crown Atlantic and Crown GT will service the Tower Revenue Notes, the Tower Revenue Notes are not obligations of, nor are the Tower Revenue Notes secured by the cash flows or any other assets of, Crown Atlantic and Crown GT. As of December 31, 2017, the Securitized Debt was collateralized with personal property and equipment with an aggregate net book value of approximately $1.1 billion, exclusive of Crown Atlantic and Crown GT personal property and equipment.

The excess cash flows from the issuers of the Securitized Debt, after the payment of principal, interest, reserves, expenses and management fees, are distributed to the Company in accordance with the terms of the indentures. If the Debt Service Coverage Ratio ("DSCR") (as defined in the applicable governing loan agreement) as of the end of any calendar quarter falls to a certain level, then all excess cash flow of the issuers of the applicable debt instrument will be deposited into a reserve account instead of being released to the Company. The funds in the reserve account will not be released to the Company until the DSCR exceeds a certain level for two consecutive calendar quarters. If the DSCR falls below a certain level as of the end of any calendar quarter, then all cash on deposit in the reserve account along with future excess cash flows of the issuers will be applied to prepay the debt with applicable prepayment consideration.

The Company may repay the Tower Revenue Notes or the 2009 Securitized Notes in whole or in part at any time after the second anniversary of the applicable issuance date, provided such prepayment is accompanied by any applicable prepayment consideration. The Securitized Debt has covenants and restrictions customary for rated securitizations, including provisions prohibiting the issuers from incurring additional indebtedness or further encumbering their assets.

See note 19 for a discussion of the redemption of the January 2010 Tower Revenue Notes.

Bonds—Senior Notes

In February 2017, the Company issued $500.0 million aggregate principal amount of 4.000% senior unsecured notes due March 2027 ("4.000% Senior Notes"). The Company used the net proceeds from the 4.000% Senior Notes offering to repay a portion of the outstanding borrowings under the 2016 Revolver.

In May 2017, the Company issued $350.0 million aggregate principal amount of 4.750% senior unsecured notes due May 2047 ("4.750% Senior Notes"). The Company used the net proceeds from the 4.750% Senior Notes offering to partially fund the Wilcon Acquisition and to repay a portion of the outstanding borrowings under the 2016 Revolver.

In August 2017, the Company issued $1.75 billion aggregate principal amount of senior unsecured notes ("August 2017 Senior Notes"), which consisted of (1) $750.0 million aggregate principal amount of 3.200% senior unsecured notes due September 2024 ("3.200% Senior Notes") and (2) $1.0 billion aggregate principal amount of 3.650% senior unsecured notes due September 2027 ("3.650% Senior Notes"). The Company used the net proceeds from the August 2017 Senior Notes offering to partially fund the Lightower Acquisition and pay related fees and expenses.

In February 2016, the Company issued $1.5 billion aggregate principal amount of senior unsecured notes ("February 2016 Senior Notes"), which consisted of (1) $600.0 million aggregate principal amount of 3.400% senior notes due February 2021 ("3.400% Senior Notes") and (2) $900.0 million aggregate principal amount of 4.450% senior unsecured notes due February 2026 ("4.450% Senior Notes"). The Company used the net proceeds from the February 2016 Senior Notes offering, together with cash on hand, to (1) repay in full all outstanding borrowings under the then outstanding 364-Day Facility and (2) repay $500.0 million of outstanding borrowings under the 2016 Revolver.

In May 2016, the Company issued $1.0 billion aggregate principal amount of senior unsecured notes ("May 2016 Senior Notes"), which consisted of (1) $250.0 million aggregate principal amount of additional 3.400% Senior Notes pursuant to the same indenture as the 3.400% Senior Notes issued in the February 2016 Senior Notes offering and (2) $750.0 million aggregate principal amount of 3.700% senior unsecured notes due June 2026 ("3.700% Senior Notes"). The Company used the net proceeds from the May 2016 Senior Notes offering to repay in full the Tower Revenue Notes, Series 2010-2 and Series 2010-5, each issued by certain of its subsidiaries, and to repay a portion of the outstanding borrowings under the 2016 Revolver.

In September 2016, the Company issued $700.0 million aggregate principal amount of 2.250% senior unsecured notes ("2.250% Senior Notes") due September 2021. The Company used the net proceeds from the 2.250% Senior Notes offering to (1) repay $500.0 million aggregate principal amount of 2.381% secured notes due 2017 ("2.381% Secured Notes") issued by certain of its subsidiaries and (2) repay a portion of the outstanding borrowings under the 2016 Revolver.

In April 2014, the Company issued $850.0 million aggregate principal amount of 4.875% senior unsecured notes due April 2022 ("4.875% Senior Notes"). The net proceeds from the offering were approximately $839.0 million, after the deduction of associated fees. The Company utilized the net proceeds from the 4.875% Senior Notes offering (1) to repay $300.0 million of the January 2010 Tower Revenue Notes with an anticipated repayment date of January 2015 and (2) to redeem all of the then outstanding 7.125% senior unsecured notes due 2019.

In October 2012, the Company issued $1.65 billion aggregate principal amount of 5.250% senior unsecured notes due 2023 ("5.250% Senior Notes"). The Company used the net proceeds from the 5.250% Senior Notes offering to partially fund the T-Mobile Acquisition.

Each of the February 2016 Senior Notes, May 2016 Senior Notes, 2.250% Senior Notes, 4.875% Senior Notes, 5.250% Senior Notes, 4.000% Senior Notes, 4.750% Senior Notes, August 2017 Senior Notes (collectively, "Senior Notes") are senior unsecured obligations of the Company and rank equally with all of the Company's existing and future senior unsecured indebtedness, including obligations under the 2016 Credit Facility, and senior to all of the Company's future subordinated indebtedness. The Senior Notes are structurally subordinated to all existing and future liabilities and obligations of the Company's subsidiaries. The Company's subsidiaries are not guarantors of the Senior Notes.

CCIC may redeem any of the Senior Notes in whole or in part at any time at a price equal to 100% of the principal amount to be redeemed, plus a make whole premium, if applicable, and accrued and unpaid interest, if any to the date of redemption.

Bonds—Secured Notes

In December 2012, the Company issued $1.0 billion aggregate principal amount of 3.849% secured notes due 2023 ("3.849% Secured Notes"). The 2012 Secured Notes were issued and are guaranteed by the same subsidiaries of CCIC that had previously issued and guaranteed the 7.750% senior unsecured notes due 2017 ("7.750% Secured Notes"). The 3.849% Secured Notes are secured by a pledge of the equity interests of such subsidiaries. The 3.849% Secured Notes are not guaranteed by and are not obligations of CCIC or any of its subsidiaries other than the issuers and guarantors of the 3.849% Secured Notes. The 3.849% Secured Notes will be paid solely from the cash flows generated from operations of the towers held directly and indirectly by the issuers and the guarantors of such notes. The Company used the net proceeds from the issuance of the 3.849% Secured Notes to repurchase and redeem the then outstanding 7.750% Secured Notes and a portion of the then outstanding 9.000% senior notes due 2011. The 3.849% Secured Notes may be redeemed at any time at a price equal to 100% of the principal amount, plus a make whole premium, and accrued and unpaid interest, if any to the redemption date.

Previously Outstanding Indebtedness

See above for a discussion of the Company's recent redemptions and repayments of debt.

Contractual Maturities

The following are the scheduled contractual maturities of the total debt or other long-term obligations outstanding at December 31, 2017. These maturities reflect contractual maturity dates and do not consider the principal payments that will commence following the anticipated repayment dates on the Tower Revenue Notes. If the Tower Revenue Notes are not paid in full on or prior to their respective anticipated repayment dates, as applicable, then the Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes and additional interest (of an additional approximately 5% per annum) will accrue on the Tower Revenue Notes.



	Years Ending December 31,
	2018		2019		2020		2021		2022		Thereafter		Total Cash Obligations		Unamortized Adjustments, Net			Total Debt and Other Obligations Outstanding
Scheduled contractual maturities	$	116,045	$	167,458	$	155,051	$	1,824,568	$	3,701,737	$	10,296,901	$	16,261,760	$	(102,140	)	$	16,159,620

Debt Purchases and Redemptions

The following is a summary of the purchases and redemptions of debt during the years ended December 31, 2017, 2016 and 2015.



	Year Ending December 31, 2017
	Principal Amount		Cash Paid		Gains (losses)^(a)
2016 Term Loan A	$	—	$	—	$	(3,525	)


(a)	The losses related to write off of deferred financing costs.



	Year Ending December 31, 2016
	Principal Amount		Cash Paid^(a)		Gains (losses)^(b)
Revolving Credit Facility under 2012 Credit Facility	$	—	$	—	$	(1,930	)
Tranche A Term Loans under 2012 Credit Facility	629,375		629,375		(1,498		)
Tranche B Term Loans under 2012 Credit Facility	2,247,015		2,247,015		(27,122		)
Tower Revenue Notes, Series 2010-2	350,000		352,796		(3,338		)
Tower Revenue Notes, Series 2010-5	300,000		307,176		(8,129		)
2.381% Secured Notes	500,000		508,472		(10,274		)
Total	$	4,026,390	$	4,044,834	$	(52,291	)


(a)	Exclusive of accrued interest.


(b)	Inclusive of $33.8 million related to the write off of deferred financing costs.



	Year Ending December 31, 2015
	Principal Amount		Cash Paid^(a)		Gains (losses)^(b)
Tower Revenue Notes, Series 2010-4	$	250,000	$	250,000	$	(159	)
WCP Securitized Notes	252,830		252,830		2,105
Tranche B Term Loans under 2012 Credit Facility	564,137		564,137		(6,127		)
Other	2,394		2,370		24
Total	$	1,069,361	$	1,069,337	$	(4,157	)


(a)	Exclusive of accrued interest.


(b)	Inclusive of $4.2 million related to the write off of deferred financing costs, premiums and discounts.

Swaps

12 Months Ended

Dec. 31, 2017

Summary of Derivative Instruments [Abstract]

Derivative Instruments and Hedging Activities Disclosure [Text Block]

Swaps

Foreign Currency Swaps

During May 2015, the Company entered into two previously outstanding foreign currency swaps to manage and reduce its foreign currency risk related to its sale of CCAL (see note 3). The Company does not enter into foreign currency swaps for speculative or trading purposes. The foreign currency swaps were originally comprised of the following:

Item Swapped

Notional

Amount

Forward Rate

Start Date

End Date

Pay Amount

Receive Amount

Fair Value at

December 31, 2017

May 2015 cash receipt from sale of CCAL

A$1,400,000

0.8072

May 2015

June 2015

Australian Dollar

US Dollar

N/A

^(a)

Installment payment from Buyer

A$155,000

0.79835

May 2015

January 2016

Australian Dollar

US Dollar

N/A

^(b)


(a)	In conjunction with closing the CCAL sale on May 28, 2015, the Company cash settled the swap with a notional value of Australian dollar $1.4 billion and recorded a gain on foreign currency swaps of $54.5 million, which is included as a component of "other income (expense)" on the Company's consolidated statement of operations.

(b)

As of December 31, 2015, the Company marked-to-market the swap with a notional value of Australian dollar $155.0 million and recorded (1) an asset within "other current assets" on the Company's consolidated balance sheet and (2) a corresponding gain on foreign currency swaps, which is included as a component of "other income (expense)" on the Company's consolidated statement of operations. In January 2016, the then outstanding swap related to the installment payment received from the Buyer was settled.

In total, the Company recorded a gain on foreign currency swaps of $65.2 million for the year ended December 31, 2015, respectively. This gain is included as a component of "other income (expense)" on the Company's consolidated statement of operations.

Fair Value Disclosures

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures

Fair Value Disclosures

The following table shows the estimated fair values of the Company's financial instruments, along with the carrying amounts of the related assets (liabilities). See also note 2.



	Level in Fair Value Hierarchy	December 31, 2017				December 31, 2016
	Level in Fair Value Hierarchy	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	1	$	314,094	$	314,094	$	567,599	$	567,599
Restricted cash	1	126,065		126,065		129,547		129,547
Liabilities:
Debt and other obligations	2	$	16,159,620	$	16,643,725	$	12,171,142	$	12,660,013

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2017

Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]

Income Taxes

Income (loss) from continuing operations before income taxes by geographic area is as follows:



	Years Ended December 31,
	2017		2016		2015
Domestic	$	450,771	$	349,041	$	461,293
Foreign^(a)	19,822		24,813		12,536
Total	$	470,593	$	373,854	$	473,829


(a)	Inclusive of income (loss) before income taxes from Puerto Rico.

The benefit (provision) for income taxes consists of the following:



	Years Ended December 31,
	2017			2016			2015
Current:
Federal	$	(2,816	)	$	(227	)	$	495
Foreign	(6,050		)	(6,820		)	(5,675		)
State	(2,289		)	(1,231		)	(3,981		)
Total current	(11,155		)	(8,278		)	(9,161		)
Deferred:
Federal	(17,743		)	(7,968		)	44,716
Foreign	2,883			(601		)	(1,048		)
State	(28		)	(34		)	16,950
Total deferred	(14,888		)	(8,603		)	60,618
Total tax benefit (provision)	$	(26,043	)	$	(16,881	)	$	51,457

A reconciliation between the benefit (provision) for income taxes and the amount computed by applying the federal statutory income tax rate to the income (loss) before income taxes is as follows:



	Years Ended December 31,
	2017			2016			2015
Benefit (provision) for income taxes at statutory rate	$	(164,707	)	$	(130,849	)	$	(165,840	)
Tax effect of foreign income (losses)	(430		)	1,215			(527		)
Tax adjustment related to REIT operations	158,812			121,092			186,649
Tax adjustment related to the inclusion of small cells in the REIT^(a)	—			—			33,759
Expenses for which no federal tax benefit was recognized	(42		)	(43		)	(414		)
Valuation allowances	21			(21		)	3,000
State tax (provision) benefit, net of federal	(2,115		)	(1,085		)	1,210
Foreign tax	(3,168		)	(7,421		)	(6,723		)
Effects of tax law change^(b)	(14,628		)	—			—
Other	214			231			343
Total	$	(26,043	)	$	(16,881	)	$	51,457


(a)	During the fourth quarter of 2015, the Company de-recognized the net deferred tax liabilities related to the Company's small cells previously included in one or more TRSs in conjunction with the inclusion of small cells in the REIT in January 2016.


(b)	Pursuant to the Tax Cuts and Jobs Act, which was signed into law in December 2017, the Company was required to write down its net federal deferred tax asset in the amount of $16.8 million as a result of the reduction in the federal corporate tax rate offset by a benefit of $2.2 million related to the refund of the Company's alternative minimum tax credit carryforward.

The components of the net deferred income tax assets and liabilities are as follows:



	December 31,
	2017			2016
Deferred income tax liabilities:
Property and equipment	$	4,940		$	3,945
Deferred site rental receivable	6,907			6,192
Total deferred income tax liabilities	11,847			10,137
Deferred income tax assets:
Intangible assets	4,460			22,377
Net operating loss carryforwards	20,800			21,143
Deferred ground lease payable	2,060			1,646
Accrued liabilities	5,161			5,511
Receivables allowance	317			383
Other	1,431			1,726
Valuation allowances	(1,172		)	(6,627		)
Total deferred income tax assets, net	33,057			46,159
Net deferred income tax asset (liabilities)	$	21,210		$	36,022

The Company operates as a REIT for U.S. federal income tax purposes.

The components of the net deferred income tax assets (liabilities) are as follows:



	December 31, 2017									December 31, 2016
Classification	Gross			Valuation Allowance			Net			Gross			Valuation Allowance			Net
Federal	$	25,260		$	—		$	25,260		$	42,948		$	(21	)	$	42,927
State	1,142			—			1,142			1,170			—			1,170
Foreign	(4,020		)	(1,172		)	(5,192		)	(1,469		)	(6,606		)	(8,075		)
Total	$	22,382		$	(1,172	)	$	21,210		$	42,649		$	(6,627	)	$	36,022

At December 31, 2017, the Company had U.S. federal and state NOLs of approximately $1.5 billion and $0.6 billion, respectively, which are available to offset future taxable income. These amounts include approximately $237.0 million of losses related to stock-based compensation. The Company also has foreign NOLs of $53.2 million. If not utilized, the Company's U.S. federal NOLs expire starting in 2024 and ending in 2036, the state NOLs expire starting in 2018 and ending in 2036, and the foreign NOLs expire starting in 2022 and ending in 2037. The utilization of the NOLs is subject to certain limitations. The Company's U.S. federal and state income tax returns generally remain open to examination by taxing authorities until three years after the applicable NOLs have been used or expired. The remaining valuation allowance relates to certain foreign net deferred tax assets (primarily NOLs).

As of December 31, 2017, there were no unrecognized tax benefits that would impact the effective tax rate, if recognized. The aggregate changes in the balance of unrecognized tax benefits are as follows:



	Years Ended December 31,
	2017			2016
Balance at beginning of year	$	3,080		$	6,770
Additions based on prior year tax positions	—			116
Reductions as a result of the lapse of statute limitations	(3,080		)	(3,806		)
Balance at end of year	$	—		$	3,080

From time to time, the Company is subject to examinations by various tax authorities in jurisdictions in which the Company has business operations. At this time, the Company is not subject to an Internal Revenue Service examination. The Australian Taxation Office is conducting an audit of the tax consequences for Australian tax purposes of the Company's sale of CCAL. The Company regularly assesses the likelihood of additional assessments in each of the tax jurisdictions. The Company believes it has adequately provided for uncertain tax positions and does not believe assessments, if any, arising from current or future examination or audits will have a material effect on the Company's financial statements.

As of December 31, 2017, the Company's deferred tax assets are included in "long-term prepaid rent and other assets, net" and the Company's deferred tax liabilities are included in "other long-term liabilities" on the Company's consolidated balance sheet.

Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Stockholders' Equity

Equity

"At-The-Market" Stock Offering Program

The Company maintains an "at-the-market" stock offering program ("ATM Program") through which it may, from time to time, issue and sell shares of its common stock having an aggregate cumulative gross sales price of up to $500.0 million to or through sales agents. Sales, if any, under the ATM Program may be made by means of ordinary brokers' transactions on the New York Stock Exchange or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or, subject to specific instructions of the Company, at negotiated prices. The Company intends to use the net proceeds from any sales under the ATM Program for general corporate purposes, which may include the funding of future acquisitions or investments and the repayment or repurchase of any outstanding indebtedness. During the year ended December 31, 2017, 0.2 million shares of common stock were sold under the ATM Program, generating net proceeds of $22.0 million after giving effect to sales commissions of $0.2 million. During the year ended December 31, 2016, 3.8 million shares of common stock were sold under the ATM Program, generating net proceeds of $323.8 million after giving effect to sales agent commissions of $3.3 million. The net proceeds from the sales under the ATM Program were used, in part, to fund the TDC Acquisition. As of December 31, 2017, the Company had approximately $150 million of gross sales of common stock availability remaining under the ATM Program.

May 2017 Common Stock Offering

On May 1, 2017, the Company completed an offering of 4.75 million shares of its common stock, which generated net proceeds of approximately $442.0 million ("May 2017 Common Stock Offering"). The Company used the net proceeds of the May 2017 Common Stock Offering to partially fund the Wilcon Acquisition.

July 2017 Equity Offerings

On July 26, 2017, the Company completed an offering of 40.15 million shares of common stock, including certain additional shares sold pursuant to the underwriters' option, which generated net proceeds of approximately $3.8 billion ("July 2017 Common Stock Offering"). The Company used the net proceeds of the July 2017 Common Stock Offering to partially fund the Lightower Acquisition and pay related fees and expenses.

On July 26, 2017, the Company completed an offering of 1.65 million shares of the Company's 6.875% Convertible Preferred Stock, at $1,000 per share, including certain additional shares sold pursuant to the underwriters' option, which generated net proceeds of approximately $1.6 billion ("Mandatory Convertible Preferred Stock Offering"). The Company used the net proceeds from the Mandatory Convertible Preferred Stock Offering to partially fund the Lightower Acquisition and pay related fees and expenses.

The holders of the 6.875% Convertible Preferred Stock are entitled to receive cumulative dividends, when and if declared by the Company's board of directors, at the rate of 6.875% on the liquidation preference of $1,000 per share. The dividends may be paid in cash or, subject to certain limitations, in shares of the Company's common stock or any combination of cash and shares of common stock on February 1, May 1, August 1 and November 1 of each year, commencing on November 1, 2017 and to, and including, August 1, 2020. The terms of the 6.875% Convertible Preferred Stock provide that, unless accumulated dividends have been paid or set aside for payment on all outstanding shares of 6.875% Convertible Preferred Stock for all past dividend periods, no dividends may be declared or paid on common stock.

Unless converted earlier, each outstanding share of the 6.875% Convertible Preferred Stock will automatically convert into shares of the Company's common stock on August 1, 2020 into between 8.6806 and 10.4167 shares of the Company's common stock, depending on the applicable market value of the common stock and subject to certain anti-dilution adjustments. At any time prior to August 1, 2020, holders of the 6.875% Convertible Preferred Stock may elect to convert all or a portion of their shares into common stock at the minimum conversion rate of 8.6806, subject to certain anti-dilution adjustments.

The July 2017 Common Stock Offering and Mandatory Convertible Preferred Stock Offering are collectively referred to herein as "July 2017 Equity Offerings."

Convertible Preferred Stock Conversion

In October and November 2016, all of the approximately 9.8 million shares of the Company's then outstanding 4.50% Convertible Preferred Stock converted to approximately 11.6 million shares of the Company's common stock at a conversion rate (based on the applicable market value of the common stock and subject to certain anti-dilutive adjustments) of 1.1880 common shares per each share of 4.50% Convertible Preferred Stock.

November 2016 Common Stock Offering

In November 2016, the Company completed an equity offering of approximately 11.4 million shares of common stock, which generated net proceeds of approximately $1.0 billion ("November 2016 Common Stock Offering"). The Company utilized proceeds from such offering to partially fund the FiberNet Acquisition.

Declaration and Payment of Dividends

During the year ended December 31, 2017, the following dividends were declared or paid:



Equity Type	Declaration Date	Record Date	Payment Date	Dividends Per Share		Aggregate Payment Amount (In millions)
Common Stock	February 17, 2017	March 17, 2017	March 31, 2017	$	0.950	$	343.3	^(a)
Common Stock	May 18, 2017	June 16, 2017	June 30, 2017	$	0.950	$	350.3	^(a)
Common Stock	August 3, 2017	September 15, 2017	September 29, 2017	$	0.950	$	389.6	^(a)
Common Stock	October 15, 2017	December 15, 2017	December 29, 2017	$	1.050	$	428.8	^(a)
6.875% Convertible Preferred Stock	September 21, 2017	October 15, 2017	November 1, 2017	$	18.142	$	29.9
6.875% Convertible Preferred Stock	December 15, 2017	January 15, 2018	February 1, 2018	$	17.188	$	28.4


(a)	Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest.

See note 19 for further discussion of common stock dividends.

Tax Treatment of Dividends

The following table summarizes, for income tax purposes, the nature of dividends paid during 2017 on the Company's common stock and 6.875% Convertible Preferred Stock.



Equity Type	Payment Date	Dividends Per Share		Ordinary Taxable Dividend Per Share		Qualified Taxable Dividend Per Share^(a)		Long-Term Capital Gain Distribution Per Share		Non-Taxable Distribution (per share)
Common Stock	March 31, 2017	$	0.950	$	0.950	$	0.347	$	—	$	—
Common Stock	June 30, 2017	$	0.950	$	0.950	$	0.347	$	—	$	—
Common Stock	September 29, 2017	$	0.950	$	0.950	$	0.347	$	—	$	—
Common Stock	December 29, 2017	$	1.050	$	1.050	$	0.384	$	—	$	—
6.875% Convertible Preferred Stock	November 1, 2017	$	18.142	$	18.142	$	6.629	$	—	$	—


(a)	Qualified taxable dividend amounts are included in ordinary taxable dividend amounts.

The Company has determined that none of the distributions to the Company's shareholders for the tax year ended December 31, 2017 consisted of an alternative minimum tax adjustment.

Purchases of the Company's Common Stock

During each of the years ended December 31, 2017, 2016 and 2015, the Company purchased 0.3 million shares of common stock utilizing $23.3 million, $24.9 million and $29.7 million in cash, respectively.

Stock-based Compensation

12 Months Ended

Dec. 31, 2017

Share-based Compensation [Abstract]

Stock-based Compensation

Stock Compensation Plans

Pursuant to a stockholder approved plan, the Company has and is permitted to grant stock-based awards to certain employees, consultants or non-employee directors of the Company and its subsidiaries or affiliates. As of December 31, 2017, the Company has 11.2 million shares available for future issuance pursuant to its 2013 Long-Term Incentive Plan ("LTI Plan"). Of these shares remaining available for future issuance, approximately 3.0 million may be issued pursuant to outstanding RSUs granted under the LTI Plan.

Restricted Stock Units

The Company issues RSUs to certain executives and employees; each RSU represents a contingent right to receive one share of common stock subject to satisfaction of the applicable vesting terms. The RSUs granted to certain executives and employees include (1) annual performance awards that often include provisions for forfeiture by the employee if certain market performance of the Company's common stock is not achieved, (2) new hire or promotional awards that generally contain only service conditions, or (3) other awards related to specific business initiatives or compensation objectives including retention and merger integration. Generally, such awards vest over periods of approximately 3 years.

The following is a summary of the RSU activity during the year ended December 31, 2017.



	RSUs
	(In thousands)
Outstanding at the beginning of year	2,677
Granted	1,359
Vested	(747	)
Forfeited	(321	)
Outstanding at end of year	2,968

The Company granted approximately 1.3 million, 1.3 million and 1.0 million RSUs to the Company's executives and certain other employees for each of the years ended December 31, 2017, 2016 and 2015, respectively. The weighted-average grant-date fair value per share of the grants for the years ended December 31, 2017, 2016 and 2015 was $73.52, $68.53 and $69.96 per share, respectively. The weighted-average requisite service period for the RSUs granted during 2017 was approximately 2.5 years.

The approximately 1.3 million RSUs granted during the year ended December 31, 2017, were comprised of (1) approximately 0.7 million RSUs that time vest over a three-year period and (2) approximately 0.6 million RSUs to the Company's executives and certain other employees which may vest on the third anniversary of the grant date based upon the Company's total shareholder returns (defined as share price appreciation plus the value of dividends paid during the performance period) compared to that of selected peer companies. Certain RSU agreements contain provisions that result in forfeiture by the employee of any unvested shares in the event that the Company's common stock does not achieve certain performance targets. To the extent that the requisite service is rendered, compensation cost for accounting purposes is not reversed; rather, it is recognized regardless of whether or not the market performance target is achieved.

The following table summarizes the assumptions used in the Monte Carlo simulation to determine the grant-date fair value for the awards granted during the years ended December 31, 2017, 2016 and 2015, respectively, with market conditions.



	Years Ended December 31,
	2017		2016		2015
Risk-free rate	1.5	%	0.9	%	1.0	%
Expected volatility	18	%	19	%	19	%
Expected dividend rate	4.4	%	4.2	%	4.2	%

The Company recognized aggregate stock-based compensation expense related to RSUs of $88.7 million, $76.3 million and $57.1 million for the years ended December 31, 2017, 2016 and 2015, respectively. The aggregate unrecognized compensation (net of estimated forfeitures) related to RSUs at December 31, 2017 is $72.9 million and is estimated to be recognized over a weighted-average period of less than one year.

The following table is a summary of the awards vested during the years ended December 31, 2017, 2016 and 2015.



Years Ended December 31,	Total Shares Vested	Fair Value on Vesting Date
	(In thousands of shares)
2017	747	$	67,241
2016	828	71,325
2015	946	83,244

Stock-based Compensation

The following table discloses the components of stock-based compensation expense.



	Years Ended December 31,
	2017		2016		2015
Stock-based compensation expense:
Site rental costs of operations	$	14,942	$	14,371	$	8,969
Network services and other costs of operations	4,961		7,717		5,370
General and administrative expenses	76,532		74,450		52,809
Total stock-based compensation	$	96,435	$	96,538	$	67,148

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2017
Commitments and Contingencies [Abstract]
Commitments and Contingencies	Commitments and Contingencies The Company is involved in various claims, lawsuits, or proceedings arising in the ordinary course of business. While there are uncertainties inherent in the ultimate outcome of such matters and it is impossible to presently determine the ultimate costs or losses that may be incurred, if any, management believes the resolution of such uncertainties and the incurrence of such costs should not have a material adverse effect on the Company's consolidated financial position or results of operations. Additionally, the Company and certain of its subsidiaries are contingently liable for commitments or performance guarantees arising in the ordinary course of business, including certain letters of credit or surety bonds. See note 15 for a discussion of the operating lease commitments. In addition, see note 1 for a discussion of the Company's option to purchase approximately 53% of its towers at the end of their respective lease terms. The Company has no obligation to exercise such purchase options.

Leases

12 Months Ended

Dec. 31, 2017

Leases [Abstract]

Leases

Operating Leases

Tenant Leases

The following table is a summary of the rental cash payments owed to the Company, as a lessor, by tenants pursuant to contractual agreements in effect as of December 31, 2017. Generally, the Company's leases with its tenants provide for (1) annual escalations, (2) multiple renewal periods at the tenant's option, and (3) only limited termination rights at the applicable tenant's option through the current term. As of December 31, 2017, the weighted-average remaining term of tenant leases is approximately five years, exclusive of renewals at the tenant's option. The tenants' rental payments included in the table below are through the current terms with a maximum current term of 20 years and do not assume exercise of tenant renewal options.



	Years Ending December 31,
	2018		2019		2020		2021		2022		Thereafter		Total
Tenant leases	$	3,401,845	$	3,277,019	$	3,160,514	$	3,028,825	$	2,805,519	$	5,628,294	$	21,302,016

Operating Leases

The following table is a summary of rental cash payments owed by the Company, as lessee, to landlords pursuant to contractual agreements in effect as of December 31, 2017. The Company is obligated under non-cancelable operating leases for land interests under 76% of its towers. The majority of these lease agreements have (1) certain termination rights that provide for cancellation after a notice period, (2) multiple renewal options at the Company's option, and (3) annual escalations. Lease agreements may also contain provisions for a contingent payment based on revenues or the gross margin derived from the communications infrastructure located on the leased land interest. Approximately 75% and approximately 90% of the Company's Towers site rental gross margins for the year ended December 31, 2017 are derived from towers where the land interest under the tower is owned or leased with final expiration dates of greater than 20 years and ten years, respectively, inclusive of renewals at the Company's option. The operating lease payments included in the table below include payments for certain renewal periods at the Company's option up to the estimated communications infrastructure useful life of 20 years and an estimate of contingent payments based on revenues and gross margins derived from existing tenant leases.



	Years Ending December 31,
	2018		2019		2020		2021		2022		Thereafter		Total
Operating leases	$	635,321	$	632,775	$	622,587	$	617,951	$	609,796	$	7,941,187	$	11,059,617

Rental expense from operating leases was $710.2 million, $677.9 million, and $657.1 million, respectively, for the years ended December 31, 2017, 2016, and 2015. The rental expense was inclusive of contingent payments based on revenues or gross margin derived from the communications infrastructure located on the leased land interests of $100.1 million, $96.9 million, and $91.8 million, respectively, for the years ended December 31, 2017, 2016, and 2015.

Operating Segments and Concentrations of Credit Risk

12 Months Ended

Dec. 31, 2017

Operating Segments and Concentrations of Credit Risks

Operating Segments and Concentrations of Credit Risk

Operating Segments

As a result of the 2017 Acquisitions of fiber assets (see note 4), the Company changed the name of the "Small Cells" operating segment to "Fiber." The Company changed the name of this segment to reflect its strategy of utilizing the same fiber assets to provide both small cells and fiber solutions to its customers. The name change did not impact the composition or previously-reported operating results of the Fiber segment. As such, the Company's operating segments are now referred to as "Towers" and "Fiber."

The Towers segment provides access, including space or capacity, to the Company's approximately 40,000 towers geographically dispersed throughout the U.S. The Towers segment also reflects certain network services relating to the Company's towers, consisting of site development services and installation services. The Fiber segment provides access, including space or capacity, to the Company's approximately 60,000 route miles of fiber primarily supporting small cells and fiber solutions.

The measurement of profit or loss used by the Company's chief operating decision maker ("CODM") to evaluate the results of operations of its operating segments are (1) segment site rental gross margin, (2) segment network services and other gross margin and (3) segment operating profit. The Company defines segment site rental gross margin as segment site rental revenues less segment site rental cost of operations, which excludes stock-based compensation expense and prepaid lease purchase price adjustments recorded in consolidated cost of operations. The Company defines segment network services and other gross margin as segment network services and other revenues less segment network services and other cost of operations, which excludes stock-based compensation expense recorded in consolidated cost of operations. The Company defines segment operating profit as segment site rental gross margin plus segment network services and other gross margin, less general and administrative expenses attributable to the respective segment.

Costs that are directly attributable to Towers and Fiber are assigned to those respective segments. The "Other" column (1) represents amounts excluded from specific segments, such as restructuring charges (credits), asset write-down charges, acquisition and integration costs, depreciation, amortization and accretion, amortization of prepaid lease purchase price adjustments, interest expense and amortization of deferred financing costs, gains (losses) on retirement of long-term obligations, net gain (loss) on interest rate swaps, gains (losses) on foreign currency swaps, impairment of available-for-sale securities, interest income, other income (expense), cumulative effect of a change in accounting principle, income (loss) from discontinued operations, and stock-based compensation expense and (2) reconciles segment operating profit to income (loss) before income taxes, as the amounts are not utilized in assessing each segment's performance. The "Other" total assets balance includes corporate assets such as cash and cash equivalents which have not been allocated to specific segments. There are no significant revenues resulting from transactions between the Company's operating segments.



	Year Ended December 31, 2017
	Towers		Fiber		Other			Consolidated Total
Segment site rental revenues	$	2,899,554	$	769,637				$	3,669,191
Segment network services and other revenues	636,532		49,882					686,414
Segment revenues	3,536,086		819,519					4,355,605
Segment site rental cost of operations	844,795		264,059					1,108,854
Segment network services and other cost of operations	374,134		40,691					414,825
Segment cost of operations^(a)	1,218,929		304,750					1,523,679
Segment site rental gross margin	2,054,759		505,578					2,560,337
Segment network services and other gross margin	262,398		9,191					271,589
Segment general and administrative expenses^(a)	93,662		89,048		167,455			350,165
Segment operating profit (loss)	2,223,495		425,721		(167,455		)	2,481,761
Stock-based compensation expense					96,435			96,435
Depreciation, amortization and accretion					1,242,408			1,242,408
Interest expense and amortization of deferred financing costs					590,682			590,682
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes^(b)					81,643			81,643
Income (loss) from continuing operations before income taxes								$	470,593
Capital expenditures	$	418,476	$	782,409	$	27,186		$	1,228,071
Total assets (at year end)	$	17,940,893	$	13,669,636	$	619,041		$	32,229,570
Total goodwill (at year end)	$	5,127,259	$	4,894,209	$	—		$	10,021,468


(a)	Segment cost of operations excludes (1) stock-based compensation expense of $19.9 million for the year ended December 31, 2017 and (2) prepaid lease purchase price adjustments of $20.1 million for the year ended December 31, 2017. Segment general and administrative expenses exclude stock-based compensation expense of $76.5 million for the year ended December 31, 2017.


(b)	See consolidated statement of operations for further information.



	Year Ended December 31, 2016
	Towers		Fiber		Other			Consolidated Total
Segment site rental revenues	$	2,830,708	$	402,599				$	3,233,307
Segment network services and other revenues	603,689		84,229					687,918
Segment revenues	3,434,397		486,828					3,921,225
Segment site rental cost of operations	840,209		147,459					987,668
Segment network services and other cost of operations	344,595		64,859					409,454
Segment cost of operations^(a)	1,184,804		212,318					1,397,122
Segment site rental gross margin	1,990,499		255,140					2,245,639
Segment network services and other gross margin	259,094		19,370					278,464
Segment general and administrative expenses^(a)	92,903		60,676		143,001			296,580
Segment operating profit (loss)	2,156,690		213,834		(143,001		)	2,227,523
Stock-based compensation expense					96,538			96,538
Depreciation, amortization and accretion					1,108,551			1,108,551
Interest expense and amortization of deferred financing costs					515,032			515,032
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes^(b)					133,548			133,548
Income (loss) from continuing operations before income taxes								$	373,854
Capital expenditures	$	429,526	$	409,710	$	34,647		$	873,883
Total assets (at year end)	$	18,394,572	$	3,440,600	$	839,920		$	22,675,092
Total goodwill (at year end)	$	5,114,639	$	643,037	$	—		$	5,757,676


(a)	Segment cost of operations excludes (1) stock-based compensation expense of $22.1 million for the year ended December 31, 2016 and (2) prepaid lease purchase price adjustments of $21.3 million for the year ended December 31, 2016. Segment general and administrative expenses exclude stock-based compensation expense of $74.5 million for the year ended December 31, 2016.


(b)	See consolidated statement of operations for further information.



	Year Ended December 31, 2015
	Towers		Fiber		Other			Consolidated Total
Segment site rental revenues	$	2,734,045	$	284,368				$	3,018,413
Segment network services and other revenues	591,655		53,783					645,438
Segment revenues	3,325,700		338,151					3,663,851
Segment site rental cost of operations	827,175		107,195					934,370
Segment network services and other cost of operations	309,025		43,162					352,187
Segment cost of operations^(a)	1,136,200		150,357					1,286,557
Segment site rental gross margin	1,906,870		177,173					2,084,043
Segment network services and other gross margin	282,630		10,621					293,251
Segment general and administrative expenses^(a)	91,899		38,379		127,833			258,111
Segment operating profit (loss)	2,097,601		149,415		(127,833		)	2,119,183
Stock-based compensation expense					67,148			67,148
Depreciation, amortization and accretion					1,036,178			1,036,178
Interest expense and amortization of deferred financing costs					527,128			527,128
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes^(b)					14,900			14,900
Income (loss) from continuing operations before income taxes								$	473,829
Capital expenditures	$	564,753	$	314,882	$	29,257		$	908,892
Total assets (at year end)	$	17,974,847	$	3,511,956	$	450,163		$	21,936,966
Total goodwill (at year end)	$	4,863,847	$	649,704	$	—		$	5,513,551


(a)	Segment cost of operations excludes (1) stock-based compensation expense of $14.3 million for the year ended December 31, 2015 and (2) prepaid lease purchase price adjustments of $20.5 million for the year ended December 31, 2015. Segment general and administrative expenses exclude stock-based compensation expense of $52.8 million for the year ended December 31, 2015.


(b)	See consolidated statement of operations for further information.

Major Customers

The following table summarizes the percentage of the consolidated revenues for those customers accounting for more than 10% of the consolidated revenues.



	Years Ended December 31,
	2017		2016		2015
AT&T	25	%	27	%	27	%
T-Mobile	22	%	23	%	22	%
Verizon Wireless	22	%	22	%	21	%
Sprint	17	%	16	%	19	%
Total	86	%	88	%	89	%

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash and cash equivalents, restricted cash and trade receivables. The Company mitigates its risk with respect to cash and cash equivalents by maintaining such deposits at high credit quality financial institutions and monitoring the credit ratings of those institutions. The Company's restricted cash is predominately held and directed by a trustee (see note 2).

The Company derives the largest portion of its revenues from customers in the wireless industry. The Company also has a concentration in its volume of business with AT&T, T-Mobile, Verizon Wireless and Sprint or their agents that accounts for a significant portion of the Company's revenues, receivables and deferred site rental receivables. The Company mitigates its concentrations of credit risk with respect to trade receivables by actively monitoring the creditworthiness of its tenants, the use of tenant leases with contractually determinable payment terms or proactive management of past due balances.

Supplemental Cash Flow Information

12 Months Ended

Dec. 31, 2017

Supplemental Cash Flow Information [Abstract]

Supplemental Cash Flow Information

The following table is a summary of the supplemental cash flow information during the years ended December 31, 2017, 2016 and 2015.



	Years Ended December 31,
	2017		2016		2015
Supplemental disclosure of cash flow information:
Interest paid	$	546,543	$	470,655	$	489,970
Income taxes paid	16,427		13,821		28,771
Supplemental disclosure of non-cash investing and financing activities:
Increase (decrease) in accounts payable for purchases of property and equipment	2,279		17,922		(7,042		)
Purchase of property and equipment under capital leases and installment land purchases	31,999		52,322		60,270
Installment payment receivable for sale of CCAL (see note 3)	—		—		117,384
Preferred stock dividends accrued but not paid (see note 12)	28,359		—		10,997

Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2017

Selected Quarterly Financial Information [Abstract]

Quarterly Financial Information (Unaudited)

Summary quarterly financial information for the years ended December 31, 2017 and 2016 is as follows:



	Three Months Ended^(a)
	March 31			June 30			September 30			December 31
2017:
Net revenues	$	1,015,942		$	1,038,335		$	1,063,238		$	1,238,090
Operating income (loss)	256,549			258,500			260,567			268,429
Gains (losses) on retirement of long-term obligations	(3,525		)	—			—			—
Benefit (provision) for income taxes	(4,369		)	(4,538		)	(2,383		)	(14,753		)
Net income (loss) attributable to CCIC stockholders	119,138			112,114			115,194			98,104
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic	$	0.33		$	0.31		$	0.22		$	0.17
Diluted	$	0.33		$	0.31		$	0.21		$	0.17
	Three Months Ended^(a)
	March 31			June 30			September 30			December 31
2016:
Net revenues	$	934,384		$	962,409		$	992,016		$	1,032,416
Operating income (loss)	211,739			231,185			244,254			262,038
Gains (losses) on retirement of long-term obligations	(30,550		)	(11,467		)	(10,274		)	—
Benefit (provision) for income taxes	(3,872		)	(3,884		)	(5,041		)	(4,084		)
Net income (loss) attributable to CCIC stockholders	47,840			86,058			98,366			124,709
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic	$	0.11		$	0.22		$	0.26		$	0.35
Diluted	$	0.11		$	0.22		$	0.26		$	0.35


(a)	The sum of quarterly information may not agree to year to date information due to rounding.

Subsequent Events

12 Months Ended

Dec. 31, 2017

Subsequent Events [Abstract]

Subsequent Events [Text Block]


19.	Subsequent Events

January 2018 Senior Notes

On January 16, 2018, the Company issued $1.75 billion aggregate principal amount of senior unsecured notes ("January 2018 Senior Notes"), which consisted of (1) $750.0 million aggregate principal amount of 3.150% senior unsecured notes due July 2023 ("3.150% Senior Notes") and (2) $1.0 billion aggregate principal amount of 3.800% senior unsecured notes due February 2028 ("3.650% Senior Notes"). The Company used the net proceeds of the January 2018 Senior Notes offering to repay (1) in full the January 2010 Tower Revenue Notes and (2) a portion of the outstanding borrowings under the 2016 Revolver.

Common Stock Dividend

On February 21, 2018, the Company declared a quarterly common stock dividend of $1.05 per share, which was approved by the Company's board of directors. The common stock dividend will be paid on March 30, 2018 to common stockholders of record as of March 16, 2018.

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2017

Schedule II Valuation and Qualifying Accounts

Schedule II - Valuation and Qualifying Accounts Disclosure [Text Block]



			Additions		Deductions
	Balance at Beginning of Year		Charged to Operations		Credited to Operations		Written Off			Effect of Exchange Rate Changes		Other Adjustments			Balance at End of Year
Allowance for Doubtful Accounts Receivable:
2017	$	11,314	$	4,360	$	—	$	(4,591	)	$	—	$	2,663	^(a)	$	13,746
2016	$	9,574	$	4,873	$	—	$	(3,133	)	$	—	$	—		$	11,314
2015	$	10,037	$	2,958	$	—	$	(3,421	)	$	—	$	—		$	9,574


(a)	Represents the allowance for doubtful accounts reflected in the preliminary purchase price allocations for the 2017 Acquisitions. See note 4.



			Additions				Deductions
	Balance at Beginning of Year		Charged to Operations		Charged to Additional Paid-in Capital and Other Comprehensive Income		Credited to Operations			Credited to Additional Paid-in Capital and Other Comprehensive Income		Other Adjustments^(a)			Balance at End of Year
Deferred Tax Valuation Allowance:
2017	$	6,627	$	59	$	—	$	(5,514	)	$	—	$	—		$	1,172
2016	$	1,994	$	586	$	—	$	(2,236	)	$	—	$	6,283		$	6,627
2015	$	21,038	$	164	$	—	$	(3,000	)	$	—	$	(16,208	)	$	1,994


(a)	Inclusive of (1) the effects of acquisitions and (2) the inclusion of small cells in the REIT in January 2016.

Schedule III - Schedule of Real Estate and Depreciation (Notes)

12 Months Ended

Dec. 31, 2017

SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]

SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Text Block]

Description

Encumbrances

Initial Cost to Company

Cost Capitalized Subsequent to Acquisition

Gross Amount Carried at Close of Current Period

Accumulated Depreciation at Close of Current Period

Date of Construction

Date Acquired

Life on Which Depreciation in Latest Income Statement is Computed

40,080 towers⁽¹⁾

4,580,581

⁽²⁾

⁽³⁾

20,109,562

⁽⁴⁾

(7,303,230

)

Various

Up to 20 years


(1)	Amount is exclusive of small cell nodes. No single tower exceeds 5% of the aggregate gross amounts at which the assets were carried at the close of the period set forth in the table above.


(2)	Certain of the Company's debt is secured by (1) a pledge of the equity interests in each applicable issuer and (2) a security interest in the applicable issuers' leases with tenants to lease tower space (space licenses).


(3)	The Company has omitted this information, as it would be impracticable to compile such information on a tower-by-tower basis.


(4)	Does not include those towers under construction.



	2017			2016
Gross amount at beginning	$	16,120,896		$	15,110,835
Additions during period:
Acquisitions through foreclosure	—			—
Other acquisitions⁽¹⁾⁽²⁾	2,787,829			130,139
Communications infrastructure construction and improvements	1,062,589			709,538
Purchase of land interests	80,647			74,579
Sustaining capital expenditures	56,480			55,417
Other⁽³⁾	46,537			95,049
Total additions	4,034,082			1,064,722
Deductions during period:
Cost of real estate sold or disposed	(45,416		)	(54,661		)
Other	—			—
Total deductions:	(45,416		)	(54,661		)
Balance at end	$	20,109,562		$	16,120,896


(1)	Inclusive of changes between the final purchase price allocation and the preliminary purchase price allocations.


(2)	Includes acquisitions of communications infrastructure.


(3)	Predominately relates to the purchase of property and equipment under capital leases and installment land purchases.



	2017			2016
Gross amount of accumulated depreciation at beginning	$	(6,446,448	)	$	(5,648,598	)
Additions during period:
Depreciation	(889,983		)	(810,549		)
Total additions	(889,983		)	(810,549		)
Deductions during period:
Amount for assets sold or disposed	26,391			24,190
Other	6,810			(11,491		)
Total deductions	33,201			12,699
Balance at end	$	(7,303,230	)	$	(6,446,448	)

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Restricted Cash

The following table is a summary of the impact of restricted cash on the statement of cash flows.



	For the years ended December 31,
	2017			2016			2015
Net cash provided by (used from) operating activities	$	847		$	(4,547	)	$	3,974
Net cash provided by (used from) investing activities	$	(26	)	$	10,541		$	(3,752	)
Net cash provided by (used from) financing activities	$	3,808		$	(7,931	)	$	16,458

Receivables Allowance

General, Leases [Policy Text Block]

Lease Accounting

Lease, Policy

Property and Equipment

Asset Retirement Obligations

Acquisition and Integration Costs

Intangible Assets

Deferred Credits

Deferred Financing Costs

Revenue Recognition

Cost of Operations

Costs of Operations

Stock-Based Compensation

Expected Volatility. The Company estimates the volatility of its common stock at the date of grant based on the historical volatility of its common stock.

Expected Dividend Rate. The expected dividend rate at the date of grant is based on the then-current dividend yield.

Risk-Free Rate. The Company bases the risk-free rate on the implied yield currently available on U.S. Treasury issues with an equivalent remaining term equal to the expected life of the award.

Interest Expense and Amortization of Deferred Financing Costs

The components of interest expense and amortization of deferred financing costs are as follows:



	Years Ended December 31,
	2017			2016			2015
Interest expense on debt obligations	$	581,314		$	500,699		$	490,002
Amortization of deferred financing costs and adjustments on long-term debt, net	19,035			19,087			21,048
Amortization of interest rate swaps	—			—			18,725
Capitalized interest	(11,545		)	(7,010		)	(4,805		)
Other	1,878			2,256			2,158
Total	$	590,682		$	515,032		$	527,128

Income Taxes

Per Share Information

A reconciliation of the numerators and denominators of the basic and diluted per share computations is as follows:



	Years Ended December 31,
	2017			2016			2015
Net income (loss) from continuing operations	$	444,550		$	356,973		$	525,286
Dividends on preferred stock	(58,294		)	(32,991		)	(43,988		)
Net income (loss) from continuing operations attributable to CCIC common stockholders for basic and diluted computations	$	386,256		$	323,982		$	481,298

Income (loss) from discontinued operations, net of tax	—			—			999,049
Less: Net income (loss) attributable to the noncontrolling interest	—			—			3,343
Net income (loss) from discontinued operations attributable to CCIC common stockholders for basic and diluted computations	—			—			995,706

Weighted-average number of common shares outstanding (in thousands):
Basic weighted-average number of common stock outstanding	381,740			340,349			333,002
Effect of assumed dilution from potential common shares relating to RSUs	1,481			530			1,060
Diluted weighted-average number of common shares outstanding	383,221			340,879			334,062
Net income (loss) attributable to CCIC common stockholders, per common share:
Income (loss) from continuing operations, basic	$	1.01		$	0.95		$	1.45
Income (loss) from discontinued operations, basic	$	—		$	—		$	2.99
Net income (loss) attributable to CCIC common stockholders, basic	$	1.01		$	0.95		$	4.44
Income (loss) from continuing operations, diluted	$	1.01		$	0.95		$	1.44
Income (loss) from discontinued operations, diluted	$	—		$	—		$	2.98
Net income (loss) attributable to CCIC common stockholders, diluted	$	1.01		$	0.95		$	4.42

Fair Values

Derivative Instruments

Swaps

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncements

No accounting pronouncements adopted during the year ended December 31, 2017 had a material impact on the Company's consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies [Abstract]

Schedule of Restricted Cash and Cash Equivalents

The following table is a summary of the impact of restricted cash on the statement of cash flows.



	For the years ended December 31,
	2017			2016			2015
Net cash provided by (used from) operating activities	$	847		$	(4,547	)	$	3,974
Net cash provided by (used from) investing activities	$	(26	)	$	10,541		$	(3,752	)
Net cash provided by (used from) financing activities	$	3,808		$	(7,931	)	$	16,458

Components of Interest Expense and Amortization of Deferred Financing Costs

The components of interest expense and amortization of deferred financing costs are as follows:



	Years Ended December 31,
	2017			2016			2015
Interest expense on debt obligations	$	581,314		$	500,699		$	490,002
Amortization of deferred financing costs and adjustments on long-term debt, net	19,035			19,087			21,048
Amortization of interest rate swaps	—			—			18,725
Capitalized interest	(11,545		)	(7,010		)	(4,805		)
Other	1,878			2,256			2,158
Total	$	590,682		$	515,032		$	527,128

Reconciliation of the Numerators and Denominators of the Basic and Diluted Per Share Computations

A reconciliation of the numerators and denominators of the basic and diluted per share computations is as follows:



	Years Ended December 31,
	2017			2016			2015
Net income (loss) from continuing operations	$	444,550		$	356,973		$	525,286
Dividends on preferred stock	(58,294		)	(32,991		)	(43,988		)
Net income (loss) from continuing operations attributable to CCIC common stockholders for basic and diluted computations	$	386,256		$	323,982		$	481,298

Income (loss) from discontinued operations, net of tax	—			—			999,049
Less: Net income (loss) attributable to the noncontrolling interest	—			—			3,343
Net income (loss) from discontinued operations attributable to CCIC common stockholders for basic and diluted computations	—			—			995,706

Weighted-average number of common shares outstanding (in thousands):
Basic weighted-average number of common stock outstanding	381,740			340,349			333,002
Effect of assumed dilution from potential common shares relating to RSUs	1,481			530			1,060
Diluted weighted-average number of common shares outstanding	383,221			340,879			334,062
Net income (loss) attributable to CCIC common stockholders, per common share:
Income (loss) from continuing operations, basic	$	1.01		$	0.95		$	1.45
Income (loss) from discontinued operations, basic	$	—		$	—		$	2.99
Net income (loss) attributable to CCIC common stockholders, basic	$	1.01		$	0.95		$	4.44
Income (loss) from continuing operations, diluted	$	1.01		$	0.95		$	1.44
Income (loss) from discontinued operations, diluted	$	—		$	—		$	2.98
Net income (loss) attributable to CCIC common stockholders, diluted	$	1.01		$	0.95		$	4.42

Discontinued Operations (Tables)

12 Months Ended

Dec. 31, 2017

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Disposal Groups, Including Discontinued Operations [Table Text Block]



Cash received from sale of CCAL^(a)	$	1,139,369
Installment payment receivable due January 2016^(a)	117,384
Total proceeds from sale of CCAL	$	1,256,753
Adjusted for:
Net assets and liabilities related to discontinued operations^(b)(c)	258,575
Transaction fees and expenses	23,059
Foreign currency translation reclassification adjustments^(d)	(25,678		)
Pre-tax gain (loss) from disposal of discontinued operations	1,000,797
Income taxes related to the sale of CCAL	(21,438		)
Gain (loss) from disposal of discontinued operations	$	979,359


(a)	Exclusive of foreign currency swaps and based on exchange rates as of May 28, 2015, which was the closing date of the Company's sale of CCAL. See note 9. The impact of fluctuations in the exchange rate subsequent to the closing date are reflected as a component of "other income (expense)" on the Company's consolidated statement of operations.


(b)	Represents net assets attributable to CCIC, net of the disposition of noncontrolling interest of $23.5 million.


(c)	Inclusive of $11.1 million of cash.


(d)	Represents foreign currency translation adjustments previously included in "accumulated other comprehensive income (loss)" on the consolidated balance sheet and reclassified to "net gain (loss) from disposal of discontinued operations, net of tax" on the consolidated statement of operations and comprehensive income (loss).



	Year Ended December 31,
	2015^(b)(c)
Total revenues	$	65,293
Total cost of operations^(a)	17,498
Depreciation, amortization and accretion	10,168
Total other expenses	10,481
Pre-tax income from discontinued operations	27,146
Benefit (provision) from income taxes	(7,456		)
Net income (loss) from discontinued operations^(d)	$	19,690


(a)	Exclusive of depreciation, amortization, and accretion shown separately.


(b)	No interest expense has been allocated to discontinued operations.


(c)	CCAL results are through May 28, 2015, which was the closing date of the Company's sale of CCAL.


(d)	Exclusive of the gain (loss) from disposal of discontinued operations, net of tax, as presented on the consolidated statement of operations.

Tabular disclosure of information related to a disposal group. Includes, but is not limited to, a discontinued operation, disposal classified as held-for-sale or disposed of by means other than sale or disposal of an individually significant component.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65878427&loc=SL51721533-107759

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721665-107760

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1474-107760

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=64827811&loc=d3e1361-107760

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721683-107760

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=84176398&loc=SL51724579-110230

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5C
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721675-107760

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 4A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721663-107760

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84176398&loc=d3e2941-110230

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 3A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721659-107760

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5A
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721671-107760

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5D
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721677-107760

+ Details

Acquisitions Acquisitions (Tables)

12 Months Ended

Dec. 31, 2017

Business Acquisition, Pro Forma Information [Table Text Block]



	Twelve Months Ended December 31,
	2017				2016
Net revenues	$	5,050,166			$	4,864,852
Income (loss) before income taxes	541,389			^(b)(c)	367,326			^(b)(c)(d)
Benefit (provision) for income taxes	(28,960		)	^(a)	(20,968		)	^(a)
Net income (loss)	$	512,429		^(b)(c)	$	346,358		^(b)(c)(d)
Basic net income (loss) attributable to CCIC common stockholders, per common share	$	0.89		^(c)(e)	$	0.51		^(c)(e)
Diluted net income (loss) attributable to CCIC common stockholders, per common share	$	0.88		^(c)(e)	$	0.51		^(c)(e)

(a)


(b)	For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to depreciation and amortization of $247.1 million and $315.9 million, respectively, related to property and equipment and intangibles recorded as a result of the 2017 Acquisitions.


(c)	Pro forma amounts include the impact of the interest expense and common stock share issuances associated with the related debt and equity financings for the 2017 Acquisitions (see above and notes 8 and 12).


(d)	Amounts are inclusive of a total of $120 million of Lightower stock-based compensation expense and acquisition and integration costs.


(e)	Pro forma amounts include the impact of the preferred stock dividends related to the Mandatory Convertible Preferred Stock Offering (as defined in note 12) for the Lightower Acquisition (see above and note 12).

Sunesys [Member]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]

The final purchase price allocation for the Sunesys Acquisition is shown below.



Final Purchase Price Allocation
Current assets	$	15,306
Property and equipment	444,394
Goodwill^(a)	331,775
Other intangible assets, net	254,079
Current liabilities	(20,233		)
Other non-current liabilities	(37,356		)
Net assets acquired^(b)	$	987,965


(a)	The final purchase price allocation for the Sunesys Acquisition resulted in the recognition of goodwill based on the Company's expectation to leverage the Sunesys fiber footprint to support new small cells. The Sunesys fiber is complementary to the Company's existing fiber assets and is located where the Company expects to see wireless carrier network investments.


(b)	Assets acquired in the Sunesys Acquisition are included in the Company's REIT and as such, no deferred taxes were recorded in connection with the Sunesys Acquisition.

Lightower Acquisition [Member]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]



Preliminary Purchase Price Allocation
Current assets	$	104,643
Property and equipment	2,197,466
Goodwill^(a)	3,116,010
Other intangible assets, net^(b)	2,177,090
Other non-current assets	28,834
Current liabilities	(172,399		)
Other non-current liabilities	(299,667		)
Net assets acquired^(c)	$	7,151,977


(a)	The preliminary purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on:


•	the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions,


•	the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,


•	the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and


•	other intangibles not qualified for separate recognition, including the assembled workforce.


(b)	Predominantly comprised of site rental contracts and customer relationships.


(c)	The vast majority of the assets will be included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition

FiberNet Acquisition [Member]

Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]



Preliminary Purchase Price Allocation
Current assets	$	52,274
Property and equipment	438,478
Goodwill^(a)	777,563
Other intangible assets, net^(b)	327,338
Other non-current assets	2,449
Current liabilities	(41,120		)
Other non-current liabilities	(36,152		)
Net assets acquired^(c)	$	1,520,830


(a)	The preliminary purchase price allocation for the FiberNet Acquisition resulted in the recognition of goodwill based on:


•	the Company's expectation to leverage the FiberNet fiber footprint to support new small cells and fiber solutions,


•	the complementary nature of the FiberNet fiber to the Company's existing fiber assets and its location in top metro markets where the Company expects to see wireless carrier network investments,


•	the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and


•	other intangibles not qualified for separate recognition, including the assembled workforce.


(b)	Predominantly comprised of site rental contracts and customer relationships.


(c)	The vast majority of the assets will be included in the Company's REIT. As such, no deferred taxes were recorded in connection with the FiberNet Acquisition.

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Major Classes of Property and Equipment

The major classes of property and equipment are as follows:



	Estimated Useful Lives	As of December 31,
	Estimated Useful Lives	2017			2016
Land^(a)	—	$	1,859,431		$	1,747,335
Buildings	40 years	119,313			110,641
Communications infrastructure assets	1-20 years	17,183,482			13,825,394
Information technology assets and other	2-7 years	372,339			278,489
Construction in process	—	898,621			456,675
Total gross property and equipment		20,433,186			16,418,534
Less: accumulated depreciation		(7,500,301		)	(6,613,219		)
Total property and equipment, net		$	12,932,885		$	9,805,315


(a)	Includes land owned in fee and perpetual easements.

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Finite-Lived Intangible Assets [Line Items]

Schedule of Goodwill

Goodwill

The changes in the carrying value of goodwill for the years ended December 31, 2017 and December 31, 2016 were as follows:



Balance as of December 31, 2015	$	5,513,551
Additions due to TDC Acquisition^(a)	210,905
Adjustments due to other acquisitions, purchase price allocations and other, net	33,220
Balance as of December 31, 2016	$	5,757,676
Additions due to FiberNet Acquisition^(b)	777,563
Additions due to Wilcon Acquisition^(b)	357,606
Additions due to Lightower Acquisition^(b)	3,116,010
Adjustments due to other acquisitions, purchase price allocations and other, net	12,613
Balance as of December 31, 2017	$	10,021,468


(a)	The final purchase price allocation for the TDC Acquisition resulted in the recognition of goodwill in the Towers segment because of the anticipated growth opportunity in the acquired tower portfolio. See note 4.


(b)	The preliminary purchase price allocation for the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition resulted in the recognition of goodwill in the Fiber segment based on:


•	the Company's expectation to leverage the FiberNet, Wilcon and Lightower fiber footprint to support new small cell and fiber solutions,


•	the complementary nature of the FiberNet, Wilcon and Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,


•	the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and


•	other intangibles not qualified for separate recognition, including the assembled workforce. See note 4.

Intangible Assets

The following is a summary of the Company's intangible assets. See note 4 for further discussion of the Company's acquisitions.



	As of December 31, 2017							As of December 31, 2016
	Gross Carrying Value^(a)		Accumulated Amortization			Net Book Value		Gross Carrying Value		Accumulated Amortization			Net Book Value
Site rental contracts and customer relationships	$	7,782,934	$	(2,156,499	)	$	5,626,435	$	5,146,301	$	(1,847,523	)	$	3,298,778
Other intangible assets	502,891		(167,567		)	335,324		497,091		(145,797		)	351,294
Total	$	8,285,825	$	(2,324,066	)	$	5,961,759	$	5,643,392	$	(1,993,320	)	$	3,650,072

Schedule of Amortization Expense

Amortization expense related to intangible assets is classified as follows on the Company's consolidated statement of operations and comprehensive income (loss):



	For Years Ended December 31,
Classification	2017		2016		2015
Depreciation, amortization and accretion	$	314,447	$	264,656	$	251,443
Site rental costs of operations	18,373		19,367		20,420
Total amortization expense	$	332,820	$	284,023	$	271,863

Site Rental Contracts and Customer Relationships [Member]

Goodwill and Finite-Lived Intangible Assets [Line Items]

Schedule of Estimated Annual Amortization Expense



	Years Ending December 31,
	2018		2019		2020		2021		2022
Estimated annual amortization	$	445,849	$	444,889	$	444,589	$	444,155	$	443,688

Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Other Liabilities [Abstract]

Other Noncurrent Liabilities

The following is a summary of the components of "other long-term liabilities" as presented on the Company's consolidated balance sheet. See also note 2.



	December 31,
	2017		2016
Deferred rental revenues	$	1,076,845	$	983,263
Deferred ground lease payable	559,556		517,281
Above market leases for land interests, net	201,542		224,126
Deferred credits, net	531,856		207,992
Asset retirement obligation	173,733		146,100
Deferred income tax liabilities	5,192		8,075
Other long-term liabilities	5,313		392
Total	$	2,554,037	$	2,087,229

Schedule of Above Market Leases

The estimated amortization expense related to above-market leases for land interests under the Company's towers recorded to site rental costs of operations for the years ending December 31, 2018 to 2022 is as follows:



	Years Ending December 31,
	2018		2019		2020		2021		2022
Above-market leases for land interests	$	18,277	$	17,674	$	16,769	$	15,667	$	14,580

Amortization of below-market tenant leases

The following table summarizes the estimated annual amounts related to below-market tenant leases expected to be amortized into site rental revenues for the years ending December 31, 2018 to 2022 are as follows:



	Years Ending December 31,
	2018		2019		2020		2021		2022
Below-market tenant leases	$	65,104	$	59,145	$	53,050	$	49,745	$	44,910

Debt and Other Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Debt and Other Obligations [Abstract]

Schedule of Long-Term Debt Instruments



	Original Issue Date	Contractual Maturity Date		Outstanding Balance as of December 31,					Stated Interest Rate as of December 31,
	Original Issue Date	Contractual Maturity Date		2017			2016		2017		^(a)
Bank debt – variable rate:
2016 Revolver	Jan. 2016	Aug. 2022		$	980,000	^(b)	$	—	2.6	%	^(c)
2016 Term Loan A	Jan. 2016	Aug. 2022		2,396,588			1,954,173		2.6	%	^(c)
Total bank debt				3,376,588			1,954,173
Securitized debt – fixed rate:
Secured Notes, Series 2009-1, Class A-1	Jul. 2009	Aug. 2019	^(d)	31,813			51,416		6.3	%
Secured Notes, Series 2009-1, Class A-2	Jul. 2009	Aug. 2029	^(d)	69,500			68,737		9.0	%
Tower Revenue Notes, Series 2010-3	Jan. 2010	Jan. 2040	^(e)(f)	1,246,106			1,244,237		6.1	%
Tower Revenue Notes, Series 2010-6	Aug. 2010	Aug. 2040	^(e)(f)	995,354			993,557		4.9	%
Tower Revenue Notes, Series 2015-1	May 2015	May 2042	^(e)(f)	297,211			296,573		3.2	%
Tower Revenue Notes, Series 2015-2	May 2015	May 2045	^(e)(f)	692,325			691,285		3.7	%
Total securitized debt				3,332,309			3,345,805
Bonds – fixed rate:
5.250% Senior Notes	Oct. 2012	Jan. 2023		1,639,207			1,637,099		5.3	%
3.849% Secured Notes	Dec. 2012	Apr. 2023		992,663			991,279		3.8	%
4.875% Senior Notes	Apr. 2014	Apr. 2022		842,090			840,322		4.9	%
3.400% Senior Notes	Feb./May 2016	Feb. 2021		849,859			849,698		3.4	%
4.450% Senior Notes	Feb. 2016	Feb. 2026		891,145			890,118		4.5	%
3.700% Senior Notes	May 2016	June 2026		742,727			741,908		3.7	%
2.250% Senior Notes	Sept. 2016	Sept. 2021		695,383			693,893		2.3	%
4.000% Senior Notes	Feb. 2017	Mar. 2027		493,833			—		4.0	%
4.750% Senior Notes	May 2017	May 2047		343,209			—		4.8	%
3.200% Senior Notes	Aug. 2017	Sept. 2024		741,859			—		3.2	%
3.650% Senior Notes	Aug. 2017	Sept. 2027		990,965			—		3.7	%
Total bonds				9,222,940			6,644,317
Other:
Capital leases and other obligations	Various	Various	^(g)	227,783			226,847		Various
Total debt and other obligations				16,159,620			12,171,142
Less: current maturities and short-term debt and other current obligations				115,251			101,749
Non-current portion of long-term debt and other long-term obligations				$	16,044,369		$	12,069,393


(a)	Represents the weighted-average stated interest rate.


(b)	As of December 31, 2017, the undrawn availability under the 2016 Revolver was $2.5 billion. See note 19.


(c)	The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.125% to 2.000%, based on the Company's senior unsecured debt rating. The Company pays a commitment fee of approximately 0.200% per annum on the undrawn available amount under the 2016 Revolver.


(d)	The Secured Notes, Series 2009-1, Class A-1 and Secured Notes, Series 2009-1, Class A-2 are collectively referred to herein as "2009 Securitized Notes."


(e)	The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes") and Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes."

(f)


(g)	The Company's capital leases and other obligations relate to land, fiber, vehicles, and other assets and bear interest rates ranging up to 10% and mature in periods ranging from less than one year to approximately 30 years.

Schedule of Maturities of Long-term Debt

Contractual Maturities



	Years Ending December 31,
	2018		2019		2020		2021		2022		Thereafter		Total Cash Obligations		Unamortized Adjustments, Net			Total Debt and Other Obligations Outstanding
Scheduled contractual maturities	$	116,045	$	167,458	$	155,051	$	1,824,568	$	3,701,737	$	10,296,901	$	16,261,760	$	(102,140	)	$	16,159,620

Schedule of Extinguishment of Debt

The following is a summary of the purchases and redemptions of debt during the years ended December 31, 2017, 2016 and 2015.



	Year Ending December 31, 2017
	Principal Amount		Cash Paid		Gains (losses)^(a)
2016 Term Loan A	$	—	$	—	$	(3,525	)


(a)	The losses related to write off of deferred financing costs.



	Year Ending December 31, 2016
	Principal Amount		Cash Paid^(a)		Gains (losses)^(b)
Revolving Credit Facility under 2012 Credit Facility	$	—	$	—	$	(1,930	)
Tranche A Term Loans under 2012 Credit Facility	629,375		629,375		(1,498		)
Tranche B Term Loans under 2012 Credit Facility	2,247,015		2,247,015		(27,122		)
Tower Revenue Notes, Series 2010-2	350,000		352,796		(3,338		)
Tower Revenue Notes, Series 2010-5	300,000		307,176		(8,129		)
2.381% Secured Notes	500,000		508,472		(10,274		)
Total	$	4,026,390	$	4,044,834	$	(52,291	)


(a)	Exclusive of accrued interest.


(b)	Inclusive of $33.8 million related to the write off of deferred financing costs.



	Year Ending December 31, 2015
	Principal Amount		Cash Paid^(a)		Gains (losses)^(b)
Tower Revenue Notes, Series 2010-4	$	250,000	$	250,000	$	(159	)
WCP Securitized Notes	252,830		252,830		2,105
Tranche B Term Loans under 2012 Credit Facility	564,137		564,137		(6,127		)
Other	2,394		2,370		24
Total	$	1,069,361	$	1,069,337	$	(4,157	)


(a)	Exclusive of accrued interest.


(b)	Inclusive of $4.2 million related to the write off of deferred financing costs, premiums and discounts.

Swaps Foreign Currency Swaps (Tables)

12 Months Ended

Dec. 31, 2017

Foreign Currency Swaps [Abstract]

Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]

Item Swapped

Notional

Amount

Forward Rate

Start Date

End Date

Pay Amount

Receive Amount

Fair Value at

December 31, 2017

May 2015 cash receipt from sale of CCAL

A$1,400,000

0.8072

May 2015

June 2015

Australian Dollar

US Dollar

N/A

^(a)

Installment payment from Buyer

A$155,000

0.79835

May 2015

January 2016

Australian Dollar

US Dollar

N/A

^(b)


(a)	In conjunction with closing the CCAL sale on May 28, 2015, the Company cash settled the swap with a notional value of Australian dollar $1.4 billion and recorded a gain on foreign currency swaps of $54.5 million, which is included as a component of "other income (expense)" on the Company's consolidated statement of operations.

(b)

Estimated Fair Values and Carrying Amounts of Assets and Liabilities

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41641-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Topic 815
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
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-Topic 815
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-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579240-113959

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41620-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Fair Value Disclosures (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures

The following table shows the estimated fair values of the Company's financial instruments, along with the carrying amounts of the related assets (liabilities). See also note 2.



	Level in Fair Value Hierarchy	December 31, 2017				December 31, 2016
	Level in Fair Value Hierarchy	Carrying Amount		Fair Value		Carrying Amount		Fair Value
Assets:
Cash and cash equivalents	1	$	314,094	$	314,094	$	567,599	$	567,599
Restricted cash	1	126,065		126,065		129,547		129,547
Liabilities:
Debt and other obligations	2	$	16,159,620	$	16,643,725	$	12,171,142	$	12,660,013

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income (Loss) from Continuing Operations Before Income Taxes

Income (loss) from continuing operations before income taxes by geographic area is as follows:



	Years Ended December 31,
	2017		2016		2015
Domestic	$	450,771	$	349,041	$	461,293
Foreign^(a)	19,822		24,813		12,536
Total	$	470,593	$	373,854	$	473,829


(a)	Inclusive of income (loss) before income taxes from Puerto Rico.

Benefit (Provision) for Income Taxes

The benefit (provision) for income taxes consists of the following:



	Years Ended December 31,
	2017			2016			2015
Current:
Federal	$	(2,816	)	$	(227	)	$	495
Foreign	(6,050		)	(6,820		)	(5,675		)
State	(2,289		)	(1,231		)	(3,981		)
Total current	(11,155		)	(8,278		)	(9,161		)
Deferred:
Federal	(17,743		)	(7,968		)	44,716
Foreign	2,883			(601		)	(1,048		)
State	(28		)	(34		)	16,950
Total deferred	(14,888		)	(8,603		)	60,618
Total tax benefit (provision)	$	(26,043	)	$	(16,881	)	$	51,457

Effective Tax Rate

A reconciliation between the benefit (provision) for income taxes and the amount computed by applying the federal statutory income tax rate to the income (loss) before income taxes is as follows:



	Years Ended December 31,
	2017			2016			2015
Benefit (provision) for income taxes at statutory rate	$	(164,707	)	$	(130,849	)	$	(165,840	)
Tax effect of foreign income (losses)	(430		)	1,215			(527		)
Tax adjustment related to REIT operations	158,812			121,092			186,649
Tax adjustment related to the inclusion of small cells in the REIT^(a)	—			—			33,759
Expenses for which no federal tax benefit was recognized	(42		)	(43		)	(414		)
Valuation allowances	21			(21		)	3,000
State tax (provision) benefit, net of federal	(2,115		)	(1,085		)	1,210
Foreign tax	(3,168		)	(7,421		)	(6,723		)
Effects of tax law change^(b)	(14,628		)	—			—
Other	214			231			343
Total	$	(26,043	)	$	(16,881	)	$	51,457


(a)	During the fourth quarter of 2015, the Company de-recognized the net deferred tax liabilities related to the Company's small cells previously included in one or more TRSs in conjunction with the inclusion of small cells in the REIT in January 2016.


(b)	Pursuant to the Tax Cuts and Jobs Act, which was signed into law in December 2017, the Company was required to write down its net federal deferred tax asset in the amount of $16.8 million as a result of the reduction in the federal corporate tax rate offset by a benefit of $2.2 million related to the refund of the Company's alternative minimum tax credit carryforward.

Components of Deferred Tax Assets and Liabilities

The components of the net deferred income tax assets and liabilities are as follows:



	December 31,
	2017			2016
Deferred income tax liabilities:
Property and equipment	$	4,940		$	3,945
Deferred site rental receivable	6,907			6,192
Total deferred income tax liabilities	11,847			10,137
Deferred income tax assets:
Intangible assets	4,460			22,377
Net operating loss carryforwards	20,800			21,143
Deferred ground lease payable	2,060			1,646
Accrued liabilities	5,161			5,511
Receivables allowance	317			383
Other	1,431			1,726
Valuation allowances	(1,172		)	(6,627		)
Total deferred income tax assets, net	33,057			46,159
Net deferred income tax asset (liabilities)	$	21,210		$	36,022

Jurisdictional Components of Deferred Tax Assets and Liabilities

The components of the net deferred income tax assets (liabilities) are as follows:



	December 31, 2017									December 31, 2016
Classification	Gross			Valuation Allowance			Net			Gross			Valuation Allowance			Net
Federal	$	25,260		$	—		$	25,260		$	42,948		$	(21	)	$	42,927
State	1,142			—			1,142			1,170			—			1,170
Foreign	(4,020		)	(1,172		)	(5,192		)	(1,469		)	(6,606		)	(8,075		)
Total	$	22,382		$	(1,172	)	$	21,210		$	42,649		$	(6,627	)	$	36,022

Schedule of Unrecognized Tax Benefits Roll Forward

The aggregate changes in the balance of unrecognized tax benefits are as follows:



	Years Ended December 31,
	2017			2016
Balance at beginning of year	$	3,080		$	6,770
Additions based on prior year tax positions	—			116
Reductions as a result of the lapse of statute limitations	(3,080		)	(3,806		)
Balance at end of year	$	—		$	3,080

Stockholders' Equity Stockholders Equity (Tables)

12 Months Ended

Dec. 31, 2017

Dividends Declared [Abstract]

Dividends Declared

During the year ended December 31, 2017, the following dividends were declared or paid:



Equity Type	Declaration Date	Record Date	Payment Date	Dividends Per Share		Aggregate Payment Amount (In millions)
Common Stock	February 17, 2017	March 17, 2017	March 31, 2017	$	0.950	$	343.3	^(a)
Common Stock	May 18, 2017	June 16, 2017	June 30, 2017	$	0.950	$	350.3	^(a)
Common Stock	August 3, 2017	September 15, 2017	September 29, 2017	$	0.950	$	389.6	^(a)
Common Stock	October 15, 2017	December 15, 2017	December 29, 2017	$	1.050	$	428.8	^(a)
6.875% Convertible Preferred Stock	September 21, 2017	October 15, 2017	November 1, 2017	$	18.142	$	29.9
6.875% Convertible Preferred Stock	December 15, 2017	January 15, 2018	February 1, 2018	$	17.188	$	28.4


(a)	Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest.

Tax Treatment of Dividends Paid [Table Text Block]

The following table summarizes, for income tax purposes, the nature of dividends paid during 2017 on the Company's common stock and 6.875% Convertible Preferred Stock.



Equity Type	Payment Date	Dividends Per Share		Ordinary Taxable Dividend Per Share		Qualified Taxable Dividend Per Share^(a)		Long-Term Capital Gain Distribution Per Share		Non-Taxable Distribution (per share)
Common Stock	March 31, 2017	$	0.950	$	0.950	$	0.347	$	—	$	—
Common Stock	June 30, 2017	$	0.950	$	0.950	$	0.347	$	—	$	—
Common Stock	September 29, 2017	$	0.950	$	0.950	$	0.347	$	—	$	—
Common Stock	December 29, 2017	$	1.050	$	1.050	$	0.384	$	—	$	—
6.875% Convertible Preferred Stock	November 1, 2017	$	18.142	$	18.142	$	6.629	$	—	$	—


(a)	Qualified taxable dividend amounts are included in ordinary taxable dividend amounts.

Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Share-based Compensation [Abstract]

Summary of Restricted Stock Awards Activity

The following is a summary of the RSU activity during the year ended December 31, 2017.



	RSUs
	(In thousands)
Outstanding at the beginning of year	2,677
Granted	1,359
Vested	(747	)
Forfeited	(321	)
Outstanding at end of year	2,968

Summary of the Assumptions Used in the Monte Carlo Simulation to Determine the Grant-Date Fair Value



	Years Ended December 31,
	2017		2016		2015
Risk-free rate	1.5	%	0.9	%	1.0	%
Expected volatility	18	%	19	%	19	%
Expected dividend rate	4.4	%	4.2	%	4.2	%

Summary of Restricted Stock Vested

The following table is a summary of the awards vested during the years ended December 31, 2017, 2016 and 2015.



Years Ended December 31,	Total Shares Vested	Fair Value on Vesting Date
	(In thousands of shares)
2017	747	$	67,241
2016	828	71,325
2015	946	83,244

Stock Based Compensation Expense

The following table discloses the components of stock-based compensation expense.



	Years Ended December 31,
	2017		2016		2015
Stock-based compensation expense:
Site rental costs of operations	$	14,942	$	14,371	$	8,969
Network services and other costs of operations	4,961		7,717		5,370
General and administrative expenses	76,532		74,450		52,809
Total stock-based compensation	$	96,435	$	96,538	$	67,148

Leases (Tables)

12 Months Ended

Dec. 31, 2017

Leases [Abstract]

Tenant Leases



	Years Ending December 31,
	2018		2019		2020		2021		2022		Thereafter		Total
Tenant leases	$	3,401,845	$	3,277,019	$	3,160,514	$	3,028,825	$	2,805,519	$	5,628,294	$	21,302,016

Operating Leases



	Years Ending December 31,
	2018		2019		2020		2021		2022		Thereafter		Total
Operating leases	$	635,321	$	632,775	$	622,587	$	617,951	$	609,796	$	7,941,187	$	11,059,617

Operating Segments and Concentrations of Credit Risk (Tables) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Amortization of prepaid lease purchase price adjustments

$ 3,669,191

$ 3,233,307

$ 3,018,413

20,100

21,300

20,500

Allocated Share-based Compensation Expense

$ 96,435

$ 96,538

$ 67,148

Concentration Risk, Percentage

86.00%

88.00%

89.00%

Sales Revenue, Services, Net

$ 686,414

$ 687,918

$ 645,438

Direct Costs of Leased and Rented Property or Equipment

4,355,605

3,921,225

3,663,851

1,108,854

987,668

934,370

Cost of Services

414,825

409,454

352,187

Direct Operating Costs

1,523,679

1,397,122

1,286,557

Segment site rental gross margin

2,560,337

2,245,639

2,084,043

Segment network services gross margin

271,589

278,464

293,251

350,165

296,580

258,111

2,481,761

2,227,523

2,119,183

Interest expense and amortization of deferred financing costs

1,242,408

1,108,551

1,036,178

590,682

515,032

527,128

Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes

81,643

133,548

14,900

Income (Loss) from Continuing Operations Before Income Taxes

470,593

373,854

473,829

32,229,570

22,675,092

21,936,966

Schedule of Segment Reporting Information, by Segment [Table Text Block]

$ 10,021,468

$ 5,757,676

$ 5,513,551



	Year Ended December 31, 2017
	Towers		Fiber		Other			Consolidated Total
Segment site rental revenues	$	2,899,554	$	769,637				$	3,669,191
Segment network services and other revenues	636,532		49,882					686,414
Segment revenues	3,536,086		819,519					4,355,605
Segment site rental cost of operations	844,795		264,059					1,108,854
Segment network services and other cost of operations	374,134		40,691					414,825
Segment cost of operations^(a)	1,218,929		304,750					1,523,679
Segment site rental gross margin	2,054,759		505,578					2,560,337
Segment network services and other gross margin	262,398		9,191					271,589
Segment general and administrative expenses^(a)	93,662		89,048		167,455			350,165
Segment operating profit (loss)	2,223,495		425,721		(167,455		)	2,481,761
Stock-based compensation expense					96,435			96,435
Depreciation, amortization and accretion					1,242,408			1,242,408
Interest expense and amortization of deferred financing costs					590,682			590,682
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes^(b)					81,643			81,643
Income (loss) from continuing operations before income taxes								$	470,593
Capital expenditures	$	418,476	$	782,409	$	27,186		$	1,228,071
Total assets (at year end)	$	17,940,893	$	13,669,636	$	619,041		$	32,229,570
Total goodwill (at year end)	$	5,127,259	$	4,894,209	$	—		$	10,021,468


(a)	Segment cost of operations excludes (1) stock-based compensation expense of $19.9 million for the year ended December 31, 2017 and (2) prepaid lease purchase price adjustments of $20.1 million for the year ended December 31, 2017. Segment general and administrative expenses exclude stock-based compensation expense of $76.5 million for the year ended December 31, 2017.


(b)	See consolidated statement of operations for further information.



	Year Ended December 31, 2016
	Towers		Fiber		Other			Consolidated Total
Segment site rental revenues	$	2,830,708	$	402,599				$	3,233,307
Segment network services and other revenues	603,689		84,229					687,918
Segment revenues	3,434,397		486,828					3,921,225
Segment site rental cost of operations	840,209		147,459					987,668
Segment network services and other cost of operations	344,595		64,859					409,454
Segment cost of operations^(a)	1,184,804		212,318					1,397,122
Segment site rental gross margin	1,990,499		255,140					2,245,639
Segment network services and other gross margin	259,094		19,370					278,464
Segment general and administrative expenses^(a)	92,903		60,676		143,001			296,580
Segment operating profit (loss)	2,156,690		213,834		(143,001		)	2,227,523
Stock-based compensation expense					96,538			96,538
Depreciation, amortization and accretion					1,108,551			1,108,551
Interest expense and amortization of deferred financing costs					515,032			515,032
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes^(b)					133,548			133,548
Income (loss) from continuing operations before income taxes								$	373,854
Capital expenditures	$	429,526	$	409,710	$	34,647		$	873,883
Total assets (at year end)	$	18,394,572	$	3,440,600	$	839,920		$	22,675,092
Total goodwill (at year end)	$	5,114,639	$	643,037	$	—		$	5,757,676


(a)	Segment cost of operations excludes (1) stock-based compensation expense of $22.1 million for the year ended December 31, 2016 and (2) prepaid lease purchase price adjustments of $21.3 million for the year ended December 31, 2016. Segment general and administrative expenses exclude stock-based compensation expense of $74.5 million for the year ended December 31, 2016.


(b)	See consolidated statement of operations for further information.



	Year Ended December 31, 2015
	Towers		Fiber		Other			Consolidated Total
Segment site rental revenues	$	2,734,045	$	284,368				$	3,018,413
Segment network services and other revenues	591,655		53,783					645,438
Segment revenues	3,325,700		338,151					3,663,851
Segment site rental cost of operations	827,175		107,195					934,370
Segment network services and other cost of operations	309,025		43,162					352,187
Segment cost of operations^(a)	1,136,200		150,357					1,286,557
Segment site rental gross margin	1,906,870		177,173					2,084,043
Segment network services and other gross margin	282,630		10,621					293,251
Segment general and administrative expenses^(a)	91,899		38,379		127,833			258,111
Segment operating profit (loss)	2,097,601		149,415		(127,833		)	2,119,183
Stock-based compensation expense					67,148			67,148
Depreciation, amortization and accretion					1,036,178			1,036,178
Interest expense and amortization of deferred financing costs					527,128			527,128
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes^(b)					14,900			14,900
Income (loss) from continuing operations before income taxes								$	473,829
Capital expenditures	$	564,753	$	314,882	$	29,257		$	908,892
Total assets (at year end)	$	17,974,847	$	3,511,956	$	450,163		$	21,936,966
Total goodwill (at year end)	$	4,863,847	$	649,704	$	—		$	5,513,551


(a)	Segment cost of operations excludes (1) stock-based compensation expense of $14.3 million for the year ended December 31, 2015 and (2) prepaid lease purchase price adjustments of $20.5 million for the year ended December 31, 2015. Segment general and administrative expenses exclude stock-based compensation expense of $52.8 million for the year ended December 31, 2015.


(b)	See consolidated statement of operations for further information.

A Summary of the Percentage of the Consolidated Revenues for Those Customers Accounting for More than 10% of the Consolidated Revenues

The following table summarizes the percentage of the consolidated revenues for those customers accounting for more than 10% of the consolidated revenues.



	Years Ended December 31,
	2017		2016		2015
AT&T	25	%	27	%	27	%
T-Mobile	22	%	23	%	22	%
Verizon Wireless	22	%	22	%	21	%
Sprint	17	%	16	%	19	%
Total	86	%	88	%	89	%

Towers [Member]

Sales Revenue, Services, Net

$ 2,899,554

$ 2,830,708

$ 2,734,045

636,532

603,689

591,655

Direct Costs of Leased and Rented Property or Equipment

3,536,086

3,434,397

3,325,700

844,795

840,209

827,175

Cost of Services

374,134

344,595

309,025

Direct Operating Costs

1,218,929

1,184,804

1,136,200

Segment site rental gross margin

2,054,759

1,990,499

1,906,870

Segment network services gross margin

262,398

259,094

282,630

93,662

92,903

91,899

2,223,495

2,156,690

2,097,601

17,940,893

18,394,572

17,974,847

5,127,259

5,114,639

4,863,847

Small Cells [Member]

Sales Revenue, Services, Net

769,637

402,599

284,368

49,882

84,229

53,783

Direct Costs of Leased and Rented Property or Equipment

819,519

486,828

338,151

264,059

147,459

107,195

Cost of Services

40,691

64,859

43,162

Direct Operating Costs

304,750

212,318

150,357

Segment site rental gross margin

505,578

255,140

177,173

Segment network services gross margin

9,191

19,370

10,621

89,048

60,676

38,379

425,721

213,834

149,415

13,669,636

3,440,600

3,511,956

4,894,209

643,037

649,704

Other [Member]

Allocated Share-based Compensation Expense

96,435

96,538

67,148

167,455

143,001

127,833

(167,455)

(143,001)

(127,833)

Interest expense and amortization of deferred financing costs

1,242,408

1,108,551

1,036,178

590,682

515,032

527,128

Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes

81,643

133,548

14,900

619,041

839,920

450,163

Selected Quarterly Financial Information [Abstract]

$ 0

Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Quarterly Financial Information (Unaudited)

Summary quarterly financial information for the years ended December 31, 2017 and 2016 is as follows:



	Three Months Ended^(a)
	March 31			June 30			September 30			December 31
2017:
Net revenues	$	1,015,942		$	1,038,335		$	1,063,238		$	1,238,090
Operating income (loss)	256,549			258,500			260,567			268,429
Gains (losses) on retirement of long-term obligations	(3,525		)	—			—			—
Benefit (provision) for income taxes	(4,369		)	(4,538		)	(2,383		)	(14,753		)
Net income (loss) attributable to CCIC stockholders	119,138			112,114			115,194			98,104
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic	$	0.33		$	0.31		$	0.22		$	0.17
Diluted	$	0.33		$	0.31		$	0.21		$	0.17
	Three Months Ended^(a)
	March 31			June 30			September 30			December 31
2016:
Net revenues	$	934,384		$	962,409		$	992,016		$	1,032,416
Operating income (loss)	211,739			231,185			244,254			262,038
Gains (losses) on retirement of long-term obligations	(30,550		)	(11,467		)	(10,274		)	—
Benefit (provision) for income taxes	(3,872		)	(3,884		)	(5,041		)	(4,084		)
Net income (loss) attributable to CCIC stockholders	47,840			86,058			98,366			124,709
Net income (loss) attributable to CCIC common stockholders, per common share:
Basic	$	0.11		$	0.22		$	0.26		$	0.35
Diluted	$	0.11		$	0.22		$	0.26		$	0.35


(a)	The sum of quarterly information may not agree to year to date information due to rounding.

Schedule II - Valuation and Qualifying Accounts Allowance for Doubtful Accounts (Tables)

12 Months Ended

Dec. 31, 2017

Valuation and Qualifying Accounts [Abstract]

Schedule II - Valuation and Qualifying Accounts Disclosure [Text Block]



			Additions		Deductions
	Balance at Beginning of Year		Charged to Operations		Credited to Operations		Written Off			Effect of Exchange Rate Changes		Other Adjustments			Balance at End of Year
Allowance for Doubtful Accounts Receivable:
2017	$	11,314	$	4,360	$	—	$	(4,591	)	$	—	$	2,663	^(a)	$	13,746
2016	$	9,574	$	4,873	$	—	$	(3,133	)	$	—	$	—		$	11,314
2015	$	10,037	$	2,958	$	—	$	(3,421	)	$	—	$	—		$	9,574


(a)	Represents the allowance for doubtful accounts reflected in the preliminary purchase price allocations for the 2017 Acquisitions. See note 4.



			Additions				Deductions
	Balance at Beginning of Year		Charged to Operations		Charged to Additional Paid-in Capital and Other Comprehensive Income		Credited to Operations			Credited to Additional Paid-in Capital and Other Comprehensive Income		Other Adjustments^(a)			Balance at End of Year
Deferred Tax Valuation Allowance:
2017	$	6,627	$	59	$	—	$	(5,514	)	$	—	$	—		$	1,172
2016	$	1,994	$	586	$	—	$	(2,236	)	$	—	$	6,283		$	6,627
2015	$	21,038	$	164	$	—	$	(3,000	)	$	—	$	(16,208	)	$	1,994


(a)	Inclusive of (1) the effects of acquisitions and (2) the inclusion of small cells in the REIT in January 2016.

Schedule III - Schedule of Real Estate and Depreciation Schedule of Real Estate and Accumulated Depreciation (Tables)

12 Months Ended

Dec. 31, 2017

SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]

SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Text Block]

Description

Encumbrances

Initial Cost to Company

Cost Capitalized Subsequent to Acquisition

Gross Amount Carried at Close of Current Period

Accumulated Depreciation at Close of Current Period

Date of Construction

Date Acquired

Life on Which Depreciation in Latest Income Statement is Computed

40,080 towers⁽¹⁾

4,580,581

⁽²⁾

⁽³⁾

20,109,562

⁽⁴⁾

(7,303,230

)

Various

Up to 20 years


(1)	Amount is exclusive of small cell nodes. No single tower exceeds 5% of the aggregate gross amounts at which the assets were carried at the close of the period set forth in the table above.


(2)	Certain of the Company's debt is secured by (1) a pledge of the equity interests in each applicable issuer and (2) a security interest in the applicable issuers' leases with tenants to lease tower space (space licenses).


(3)	The Company has omitted this information, as it would be impracticable to compile such information on a tower-by-tower basis.


(4)	Does not include those towers under construction.



	2017			2016
Gross amount at beginning	$	16,120,896		$	15,110,835
Additions during period:
Acquisitions through foreclosure	—			—
Other acquisitions⁽¹⁾⁽²⁾	2,787,829			130,139
Communications infrastructure construction and improvements	1,062,589			709,538
Purchase of land interests	80,647			74,579
Sustaining capital expenditures	56,480			55,417
Other⁽³⁾	46,537			95,049
Total additions	4,034,082			1,064,722
Deductions during period:
Cost of real estate sold or disposed	(45,416		)	(54,661		)
Other	—			—
Total deductions:	(45,416		)	(54,661		)
Balance at end	$	20,109,562		$	16,120,896


(1)	Inclusive of changes between the final purchase price allocation and the preliminary purchase price allocations.


(2)	Includes acquisitions of communications infrastructure.


(3)	Predominately relates to the purchase of property and equipment under capital leases and installment land purchases.



	2017			2016
Gross amount of accumulated depreciation at beginning	$	(6,446,448	)	$	(5,648,598	)
Additions during period:
Depreciation	(889,983		)	(810,549		)
Total additions	(889,983		)	(810,549		)
Deductions during period:
Amount for assets sold or disposed	26,391			24,190
Other	6,810			(11,491		)
Total deductions	33,201			12,699
Balance at end	$	(7,303,230	)	$	(6,446,448	)

Basis of Presentation (Details) - USD ($) $ in Millions	12 Months Ended
Basis of Presentation (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2015
Ground Lease Agreement Initial Term	5
Subject to Capital Lease with Sprint, TMO, or AT&T [Member]
Tower count as a percentage of total towers	53.00%
Leased or Operated Under Sprint Agreement [Member]
Ground Lease Agreement Initial Term	32
Purchase Option Price	$ 2,300
Tower count as a percentage of total towers	16.00%
Leased or Operated Under T-Mobile Agreement [Member]
Ground Lease Agreement Initial Term	28
Tower count as a percentage of total towers	15.00%
T-Mobile [Member]
Purchase Option Price	$ 2,000
AT&T lease or sublease in accordance with TMO Agreement [Member]
Purchase Option Price	$ 405
Tower count as a percentage of total towers	1.00%
AT&T Prior to 2025 in accordance with TMO agreement [Member]
Purchase Option Price	$ 10
CCAL [Member]
Noncontrolling Interest, Ownership Percentage by Parent		77.60%
AT&T [Member]
Ground Lease Agreement Initial Term	28
Purchase Option Price	$ 4,200
Tower count as a percentage of total towers	22.00%

Summary of Significant Accounting Policies (Details) $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) years shares	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) shares
Fair Value Measurements, Changes in Valuation Techniques	0
Net cash provided by (used from) operating activities	$ 847	$ (4,547)	$ 3,974
Net cash provided by (used from) investing activities	(26)	10,541	(3,752)
Net cash provided by (used from) financing activities	3,808	(7,931)	16,458
Capitalized Labor Costs	$ 91,900	86,100	36,700
Useful life of site rental contracts and customer relationships (years)	20 years
Revenue recognition, non-cancelable lease term, minimum (years) \| years	5
Revenue recognition, non-cancelable lease term, maximum (years) \| years	15
Portion of company site rental costs that are ground lease expenses	0.5500
Ground Lease Agreement Initial Term	5
Percentage of tax position that is likely of being realized upon ultimate settlement	50.00%
Asset write-down charges	$ 17,322	34,453	33,468
Wireless Infrastructure [Member]
Estimated useful life, maximum, in years	20 years
Wireless Infrastructure [Member] \| Maximum [Member]
Estimated useful life, maximum, in years	20 years
Towers [Member]
Estimated useful life, maximum, in years	20 years
Property, Plant and Equipment [Member]
Asset write-down charges	$ 14,300	26,900	$ 27,000
Other Current Assets [Member]
Straight-Line Site Rental Revenues	86,000	67,200
Deferred Revenue [Domain]
Straight-Line Site Rental Revenues	$ 1,300,000	$ 1,300,000
Preferred Stock [Member]
Antidilutive securities excluded from computation of earnings per share (in shares) \| shares	15.0		11.4

Summary of Significant Accounting Policies (Interest Expense and Amortization of Deferred Financing Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of Significant Accounting Policies [Abstract]
Interest expense on debt obligations	$ 581,314	$ 500,699	$ 490,002
Amortization of deferred financing costs and adjustments on long-term debt, net	19,035	19,087	21,048
Amortization of interest rate swaps	0	0	18,725
Capitalized Interest	(11,545)	(7,010)	(4,805)
Other Components	1,878	2,256	2,158
Total	$ 590,682	$ 515,032	$ 527,128

Summary of Significant Accounting Policies (Per Share Information) (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

^[1]

Sep. 30, 2017

^[1]

Jun. 30, 2017

^[1]

Mar. 31, 2017

^[1]

Dec. 31, 2016

^[1]

Sep. 30, 2016

^[1]

Jun. 30, 2016

^[1]

Mar. 31, 2016

^[1]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Earnings Per Share, Basic and Diluted, by Common Class [Line Items]

Income (Loss) from Continuing Operations

$ 444,550

$ 356,973

$ 525,286

Dividends on preferred stock

(58,294)

(32,991)

(43,988)

Net income (loss) attributable to CCIC common stockholders

386,256

323,982

1,477,004

Income (Loss) from Discontinued Operations, Net of Tax

999,049

Less: Net income (loss) attributable to the noncontrolling interest

$ 0

$ 3,343

Weighted-average common shares outstanding:

Basic weighted-average number of common stock outstanding

381,740

340,349

333,002

Diluted weighted-average number of common shares outstanding

383,221

340,879

334,062

Net income (loss) attributable to CCIC common stockholders, after deduction of dividends on preferred stock, per common share:

$ 0.17

$ 0.22

$ 0.31

$ 0.33

$ 0.35

$ 0.26

$ 0.22

$ 0.11

$ 1.01

$ 0.95

$ 4.44

Net income (loss) attributable to CCIC common stockholders, after deduction of dividends on preferred stock, per common share:

$ 0.17

$ 0.21

$ 0.31

$ 0.33

$ 0.35

$ 0.26

$ 0.22

$ 0.11

$ 1.01

$ 0.95

$ 4.42

Preferred Stock [Member]

Antidilutive securities excluded from computation of earnings per share (in shares)

15,000

11,400

Stock Options and Restricted Stock Awards [Member]

Weighted-average common shares outstanding:

Effect of assumed dilution from potential common shares relating to stock options and restricted stock awards

1,481

530

1,060

Discontinued Operations, Disposed of by Sale [Member]

Earnings Per Share, Basic and Diluted, by Common Class [Line Items]

Net income (loss) attributable to CCIC common stockholders

$ 0

$ 995,706

Discontinued Operations [Member]

Net income (loss) attributable to CCIC common stockholders, after deduction of dividends on preferred stock, per common share:

$ 0.00

$ 2.99

Continuing Operations [Member]

$ 0.00

$ 2.98

Earnings Per Share, Basic and Diluted, by Common Class [Line Items]

Net income (loss) attributable to CCIC common stockholders

$ 386,256

$ 323,982

$ 481,298

Net income (loss) attributable to CCIC common stockholders, after deduction of dividends on preferred stock, per common share:

$ 1.01

$ 0.95

$ 1.45

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

$ 1.01

$ 0.95

$ 1.44

[1]	The sum of quarterly information may not agree to year to date information due to rounding.

Discontinued Operations (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

May 28, 2015

Proceeds from Divestiture of Businesses, Net of Cash Divested

$ 1,100,000

Disposal Group, Including Discontinued Operation, Revenue

^[1],[2]

65,293

Disposal Group, Including Discontinued Operation, Costs of Goods Sold

^[1],[2],[3]

17,498

Disposal Group, Including Discontinued Operation, Depreciation and Amortization

^[1],[2]

10,168

Disposal Group, Including Discontinued Operation, Other Expense

^[1],[2]

10,481

Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax

^[1],[2]

27,146

Discontinued Operation, Tax Effect of Income (Loss) from Discontinued Operation During Phase-out Period

(7,456)

Income (Loss) from Discontinued Operations, Net of Tax

$ 0

19,690

^[1],[2],[4]

Cash Proceeds from Divestiture of Interest in Consolidated Subsidiaries

^[5]

1,139,369

Installment payment receivable for sale of subsidiary

117,384

Total Proceeds From Sale of CCAL

1,256,753

Net assets and liabilities related to discontinued operations

^[6],[7]

258,575

Transaction fees and expenses

23,059

Foreign Currency Translation Reclassification Adjustments

^[8]

(25,678)

Pre-tax Gain (Loss) from Disposal of Discontinued Operations

1,000,797

Income Taxes Related to Sale of CCAL

(21,438)

Net Gain (Loss) from Disposal of Discontinued Operations, Net of Tax

$ 0

$ 979,359

CCAL [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Noncontrolling Interest, Ownership Percentage by Parent

77.60%

Discontinued Operations [Member]

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest

$ 23,500

Disposal Group, Including Discontinued Operation, Cash and Cash Equivalents

$ 11,100

Inclusive of Foreign Currency Swap

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Installment payment receivable for sale of subsidiary

$ 124,000

Exclusive of Foreign Currency Swap

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Installment payment receivable for sale of subsidiary

^[5]

$ 117,384

[1]	CCAL results are through May 28, 2015, which was the closing date of the Company's sale of CCAL.
[2]	No interest expense has been allocated to discontinued operations.
[3]	Exclusive of depreciation, amortization, and accretion shown separately.
[4]	Exclusive of the gain (loss) from disposal of discontinued operations, net of tax, as presented on the consolidated statement of operations.
[5]	Exclusive of foreign currency swaps and based on exchange rates as of May 28, 2015, which was the closing date of the Company's sale of CCAL. See note 9. The impact of fluctuations in the exchange rate subsequent to the closing date are reflected as a component of "other income (expense)" on the Company's consolidated statement of operations.
[6]	Inclusive of $11.1 million of cash.
[7]	Represents net assets attributable to CCIC, net of the disposition of noncontrolling interest of $23.5 million.
[8]	Represents foreign currency translation adjustments previously included in "accumulated other comprehensive income (loss)" on the consolidated balance sheet and reclassified to "net gain (loss) from disposal of discontinued operations, net of tax" on the consolidated statement of operations and comprehensive income (loss).

Acquisitions (Details)
$ / shares in Units, $ in Thousands

9 Months Ended

12 Months Ended

Sep. 30, 2017

USD ($)

Dec. 31, 2017

USD ($)

$ / shares

Dec. 31, 2016

USD ($)

$ / shares

Dec. 31, 2015

USD ($)

Business Acquisition, Pro Forma Depreciation and Amortization

$ 247,100

$ 315,900

Business Acquisition, Pro Forma Revenue

$ 5,050,166

4,864,852

Fiber Miles

60,000

Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual

$ 314,100

Business Acquisition, Pro Forma Income (Loss) Before Income Taxes

^[1],[2]

$ 541,389

367,326

^[3]

Business Combination, Pro Forma Benefit (Provision) for Income Taxes

^[4]

(28,960)

(20,968)

Business Acquisition, Pro Forma Net Income (Loss)

^[1],[2]

$ 512,429

$ 346,358

^[3]

Business Acquisition, Pro Forma Earnings Per Share, Basic | $ / shares

^[2]

$ 0.89

$ 0.51

Business Acquisition, Pro Forma Earnings Per Share, Diluted | $ / shares

^[2]

$ 0.88

$ 0.51

Business Combination, Pro Forma Stock-Based Compensation, Acquisition and Integration Costs

$ 120,000

FiberNet Acquisition [Member]

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets

$ 1,500,000

52,274

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment

438,478

Business Acquisition, Goodwill, Expected Tax Deductible Amount

^[5]

777,563

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill

^[6]

327,338

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets

2,449

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities

(41,120)

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities

(36,152)

Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net

^[7]

$ 1,520,830

Business Acquisition, Date of Acquisition Agreement

11,500

Jan. 17, 2017

Sunesys [Member]

Percentage of FIber Miles

$ 1,000,000

Fiber Miles

10,000

60.00%

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets

$ 15,306

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment

444,394

Business Acquisition, Goodwill, Expected Tax Deductible Amount

^[8]

331,775

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill

254,079

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities

(20,233)

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities

(37,356)

Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net

^[9]

987,965

Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual

$ 121,700

$ 112,600

$ 41,400

AT&T [Member]

Tower count as a percentage of total towers

22.00%

TDC [Member]

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment

$ 461,000

107,000

Business Acquisition, Goodwill, Expected Tax Deductible Amount

211,000

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill

$ 140,000

Tower Count

330

Wilcon Acquisition [Member]

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment

$ 600,000

150,000

Business Acquisition, Goodwill, Expected Tax Deductible Amount

360,000

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill

$ 140,000

Business Acquisition, Date of Acquisition Agreement

1,900

Jun. 26, 2017

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Deferred Revenue

$ 40,000

Lightower Acquisition [Member]

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets

7,100,000

104,643

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment

2,197,466

Business Acquisition, Goodwill, Expected Tax Deductible Amount

^[10]

3,116,010

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill

^[11]

2,177,090

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets

28,834

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities

(172,399)

Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities

(299,667)

Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net

^[12]

$ 7,151,977

Business Acquisition, Date of Acquisition Agreement

32,000

Nov. 01, 2017

Top Metro Markets [Domain] | FiberNet Acquisition [Member]

6,000

[1]	For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to depreciation and amortization of $247.1 million and $315.9 million, respectively, related to property and equipment and intangibles recorded as a result of the 2017 Acquisitions.
[2]	Pro forma amounts include the impact of the interest expense and common stock share issuances associated with the related debt and equity financings for the 2017 Acquisitions (see above and notes 8 and 12).
[3]	Amounts are inclusive of a total of $120 million of Lightower stock-based compensation expense and acquisition and integration costs.
[4]	For the years ended December 31, 2017 and 2016, amounts are inclusive of pro forma adjustments to the benefit (provision) for income tax as a result of the Company's REIT status. The vast majority of the assets and related income from the FiberNet Acquisition, the Wilcon Acquisition, and the Lightower Acquisition are included in the Company's REIT. The remaining assets are included in the Company's TRS. For purposes of the unaudited pro forma financial results, an adjustment has been made to reflect the additional tax impact of the income related to the TRS assets.
[5]	The preliminary purchase price allocation for the FiberNet Acquisition resulted in the recognition of goodwill based on:•the Company's expectation to leverage the FiberNet fiber footprint to support new small cells and fiber solutions,•the complementary nature of the FiberNet fiber to the Company's existing fiber assets and its location in top metro markets where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce.
[6]	Predominantly comprised of site rental contracts and customer relationships.
[7]	The vast majority of the assets will be included in the Company's REIT. As such, no deferred taxes were recorded in connection with the FiberNet Acquisition
[8]	The final purchase price allocation for the Sunesys Acquisition resulted in the recognition of goodwill based on the Company's expectation to leverage the Sunesys fiber footprint to support new small cells. The Sunesys fiber is complementary to the Company's existing fiber assets and is located where the Company expects to see wireless carrier network investments.
[9]	Assets acquired in the Sunesys Acquisition are included in the Company's REIT and as such, no deferred taxes were recorded in connection with the Sunesys Acquisition.
[10]	The preliminary purchase price allocation for the Lightower Acquisition resulted in the recognition of goodwill based on:•the Company's expectation to leverage the Lightower fiber footprint to support new small cells and fiber solutions,•the complementary nature of the Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce.
[11]	Predominantly comprised of site rental contracts and customer relationships.
[12]	The vast majority of the assets will be included in the Company's REIT. As such, no deferred taxes were recorded in connection with the Lightower Acquisition.

Property and Equipment (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Less: accumulated depreciation

$ 20,433,186

$ 16,418,534

(7,500,301)

(6,613,219)

Total property and equipment, net

12,932,885

9,805,315

Depreciation expense

914,900

832,700

$ 774,900

Capital Leased Assets, Gross

4,300,000

Accumulated Depreciation on Capital Lease Assets

1,700,000

Land owned in fee and perpetual easements [Member]

^[1]

1,859,431

1,747,335

Buildings [Member]

$ 119,313

110,641

Wireless Infrastructure [Member]

40 years

$ 17,183,482

13,825,394

Information technology assets and other [Member]

20 years

Construction in Process [Member]

$ 372,339

278,489

Minimum [Member] | Wireless Infrastructure [Member]

$ 898,621

$ 456,675

Minimum [Member] | Information technology assets and other [Member]

1 year

Maximum [Member] | Wireless Infrastructure [Member]

2 years

Maximum [Member] | Information technology assets and other [Member]

20 years

Goodwill and Finite-Lived Intangible Assets [Line Items]

7 years

[1]	Includes land owned in fee and perpetual easements.

Goodwill and Intangible Assets (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Acquired Finite-lived Intangible Assets, Weighted Average Useful Life

17 years

Goodwill Period Start

$ 5,757,676

$ 5,513,551

Goodwill Period End

10,021,468

5,757,676

$ 5,513,551

Finite-lived intangible assets, gross

8,285,825

^[1]

5,643,392

Accumulated amortization of intangible assets

(2,324,066)

(1,993,320)

Finite-lived intangible assets, net

5,961,759

3,650,072

445,849

444,889

444,589

444,155

443,688

Site Rental Contracts and Customer Relationships [Member]

Goodwill and Finite-Lived Intangible Assets [Line Items]

Finite-lived intangible assets, gross

7,782,934

^[1]

5,146,301

Accumulated amortization of intangible assets

(2,156,499)

(1,847,523)

Finite-lived intangible assets, net

5,626,435

3,298,778

Other Intangible Assets [Member]

Goodwill and Finite-Lived Intangible Assets [Line Items]

Finite-lived intangible assets, gross

502,891

^[1]

497,091

Accumulated amortization of intangible assets

(167,567)

(145,797)

Finite-lived intangible assets, net

335,324

351,294

Other Acquired Goodwill [Domain]

Goodwill and Finite-Lived Intangible Assets [Line Items]

FiberNet Acquisition [Member]

12,613

33,220

Goodwill and Finite-Lived Intangible Assets [Line Items]

Wilcon Acquisition [Member]

^[2]

777,563

Goodwill and Finite-Lived Intangible Assets [Line Items]

Lightower Acquisition [Member]

^[2]

357,606

Goodwill and Finite-Lived Intangible Assets [Line Items]

Goodwill and Finite-Lived Intangible Assets [Line Items]

^[2]

3,116,010

TDC [Member]

Depreciation, Amortization and Accretion [Member]

^[3]

210,905

Goodwill and Finite-Lived Intangible Assets [Line Items]

Amortization expense

314,447

264,656

251,443

Site Rental Costs of Operations [Member]

Goodwill and Finite-Lived Intangible Assets [Line Items]

Amortization expense

18,373

19,367

20,420

Total Amortization Expense [Member]

Goodwill and Finite-Lived Intangible Assets [Line Items]

Amortization expense

$ 332,820

$ 284,023

$ 271,863

[1]	(a)During the year ended December 31, 2017, intangible assets additions (primarily site rental contracts and customer relationships) from acquisitions had a weighted average amortization period of approximately 17 years.
[2]	The preliminary purchase price allocation for the FiberNet Acquisition, Wilcon Acquisition and Lightower Acquisition resulted in the recognition of goodwill in the Fiber segment based on:•the Company's expectation to leverage the FiberNet, Wilcon and Lightower fiber footprint to support new small cell and fiber solutions,•the complementary nature of the FiberNet, Wilcon and Lightower fiber to the Company's existing fiber assets and its location where the Company expects to see wireless carrier network investments,•the Company's belief that the acquired fiber assets are well-positioned to benefit from the continued growth trends in the demand for data, and•other intangibles not qualified for separate recognition, including the assembled workforce. See note 4.
[3]	The final purchase price allocation for the TDC Acquisition resulted in the recognition of goodwill in the Towers segment because of the anticipated growth opportunity in the acquired tower portfolio. See note 4.

Other Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Liabilities [Line Items]
Asset Retirement Obligation, Accretion Expense	$ 13,100	$ 11,300	$ 9,900
Other Liabilities, non-current	2,554,037	2,087,229
Estimated Future Undiscounted Cash Flows Expected To Be Paid Relating To Asset Retirement Obligations	1,200,000
Amortization of Below Market Tenant Lease	37,300	33,600	32,800
Accrued Payroll and Other Compensation	141,000	100,900
Above Market Leases [Member]
Other Liabilities [Line Items]
Amortization of Above Market Leases	19,300	21,000	$ 22,500
Amortization expense, 2018 [Member]
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	18,277
Amortization expense, 2019 [Member]
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	17,674
Amortization expense, 2020 [Member]
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	16,769
Amortization expense, 2021 [Member]
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	15,667
Amortization expense, 2022 [Member] [Domain]
Other Liabilities [Line Items]
Expected amortization of above-market leases by year	14,580
Amortization expense, 2018 [Member]
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	65,104
Amortization expense, 2019 [Member]
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	59,145
Amortization expense, 2020 [Member] [Domain]
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	53,050
Amortization expense, 2021 [Member] [Domain]
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	49,745
Amortization expense, 2022 [Member] [Domain]
Other Liabilities [Line Items]
Expected amortization of below-market tenant leases by year	44,910
customer prepaid rent [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	1,076,845	983,263
deferred ground lease payable [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	559,556	517,281
Above Market Leases [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	201,542	224,126
deferred credits [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	531,856	207,992
asset retirement obligations [Member]
Other Liabilities [Line Items]
Asset Retirement Obligation	173,733	146,100
Deferred Tax Liability, noncurrent [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	5,192	8,075
Other Liabilities [Member]
Other Liabilities [Line Items]
Other Liabilities, non-current	$ 5,313	$ 392

Debt and Other Obligations (Indebtedness) (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

Sep. 30, 2017

^[3]

Jun. 30, 2017

^[3]

Mar. 31, 2017

^[3]

Dec. 31, 2016

Sep. 30, 2016

^[3]

Jun. 30, 2016

^[3]

Mar. 31, 2016

^[3]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2012

Oct. 01, 2012

Less: current maturities and short-term debt and other current obligations

$ 16,159,620

$ 12,171,142

$ 16,159,620

$ 12,171,142

115,251

101,749

115,251

101,749

Non-current portion of long-term debt and other long-term obligations

16,044,369

12,069,393

16,044,369

12,069,393

5.30%

Long-term Debt, Gross

16,261,760

$ 1,650,000

4,026,390

$ 1,069,361

Gains (losses) on retirement of long-term obligations

4,044,834

^[1]

1,069,337

^[2]

^[3]

$ 0

$ (3,525)

^[3]

$ (10,274)

$ (11,467)

$ (30,550)

(3,525)

(52,291)

^[4]

(4,157)

^[5]

2016 Term Loan A [Member]

Gains (losses) on retirement of long-term obligations

^[6]

$ (3,525)

Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 2 [Member]

350,000

Gains (losses) on retirement of long-term obligations

^[1]

352,796

^[4]

(3,338)

2012 Credit Facility [Member]

Line of Credit Facility, Commitment Fee Percentage

0.20%

2012 Revolver [Member]

Gains (losses) on retirement of long-term obligations

^[1]

^[4]

(1,930)

Bank Debt [Member]

Variable Rate 2012 Term Loans Tranche B [Member]

3,376,588

1,954,173

$ 3,376,588

1,954,173

2,247,015

564,137

Gains (losses) on retirement of long-term obligations

2,247,015

^[1]

564,137

^[2]

(27,122)

^[4]

$ (6,127)

^[5]

Securitized Debt [Member]

High Yield Bonds [Member]

3,332,309

3,345,805

3,332,309

3,345,805

9,222,940

6,644,317

9,222,940

6,644,317

2016 Revolver [Member]

Line of Credit Facility, Maximum Borrowing Capacity

500,000

3,500,000

$ 3,500,000

2016 Revolver [Member] | Bank Debt [Member]

Jan. 01, 2016

8/31/2022

$ 980,000

^[7]

$ 980,000

^[7]

Line of Credit Facility, Maximum Borrowing Capacity

^[8],[9]

2.60%

2,500,000

2016 Term Loan A [Member] | Bank Debt [Member]

Jan. 01, 2016

8/31/2022

$ 2,396,588

1,954,173

$ 2,396,588

1,954,173

^[8],[9]

2.60%

Fixed Rate Debt 2009 Securitized Notes A-1 [Member] | Securitized Debt [Member]

2,000,000

Jul. 01, 2009

^[10]

8/1/2019

$ 31,813

51,416

$ 31,813

51,416

Fixed Rate Debt 2009 Securitized Notes A-2 [Member] | Securitized Debt [Member]

^[8]

6.30%

Jul. 01, 2009

^[10]

8/1/2029

$ 69,500

68,737

$ 69,500

68,737

Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 3 [Member] | Securitized Debt [Member]

^[8]

9.00%

Jan. 01, 2010

^[11],[12]

1/1/2040

$ 1,246,106

1,244,237

$ 1,246,106

1,244,237

Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 6 [Member] | Securitized Debt [Member]

^[8]

6.10%

Aug. 01, 2010

^[11],[12]

8/1/2040

$ 995,354

993,557

$ 995,354

993,557

Fixed Rate Securitized Debt May 2015 Tower Revenue Notes [Member] [Domain] | Securitized Debt [Member]

^[8]

4.90%

May 01, 2015

^[11],[12]

5/1/2042

$ 297,211

296,573

$ 297,211

296,573

Fixed Rate Securitized Debt May 2015 Tower Revenue Notes 2 [Member] | Securitized Debt [Member]

^[8]

3.20%

May 01, 2015

^[11],[12]

5/1/2045

$ 692,325

691,285

$ 692,325

691,285

5.250% Senior Notes [Member] | High Yield Bonds [Member]

^[8]

3.70%

Oct. 01, 2012

1/15/2023

$ 1,639,207

1,637,099

$ 1,639,207

1,637,099

3.849% Secured Notes [Member] | High Yield Bonds [Member]

^[8]

5.30%

Dec. 01, 2012

4/15/2023

$ 992,663

991,279

$ 992,663

991,279

4.875% Senior Notes [Member] | High Yield Bonds [Member]

^[8]

3.80%

Apr. 01, 2014

4/1/2022

$ 842,090

840,322

$ 842,090

840,322

4.90%

^[8]

4.90%

^[8]

4.90%

3.400% Senior Notes [Member] | High Yield Bonds [Member]

$ 850,000

Feb. 01, 2016

2/15/2021

$ 849,859

$ 849,698

$ 849,859

$ 849,698

3.40%

^[8]

3.40%

^[8]

3.40%

4.450% Senior Notes [Member] | High Yield Bonds [Member]

$ 250,000

Feb. 01, 2016

2/15/2026

$ 891,145

$ 890,118

$ 891,145

$ 890,118

4.50%

^[8]

4.50%

^[8]

4.50%

3.700% Senior Notes [Member] | High Yield Bonds [Member]

$ 900,000

May 01, 2016

6/15/2026

$ 742,727

$ 741,908

$ 742,727

$ 741,908

3.70%

^[8]

3.70%

^[8]

3.70%

2.250% Senior Notes [Member] | High Yield Bonds [Member]

$ 750,000

Sep. 01, 2016

9/1/2021

$ 695,383

693,893

$ 695,383

693,893

4.000% Senior Unsecured Notes [Member] | High Yield Bonds [Member]

^[8]

2.30%

Feb. 01, 2017

3/1/2027

$ 493,833

^[8]

4.00%

4.750% Senior Unsecured Notes [Member] [Member] | High Yield Bonds [Member]

$ 500,000

May 01, 2017

5/1/2047

$ 343,209

^[8]

4.80%

3.200% Senior Unsecured Notes [Member] | High Yield Bonds [Member]

$ 350,000

Aug. 01, 2017

9/1/2024

$ 741,859

3.650% Senior Unsecured Notes [Member] | High Yield Bonds [Member]

^[8]

3.20%

Aug. 01, 2017

9/1/2027

$ 990,965

Capital Lease Obligations and Other [Member]

^[8]

3.70%

Original Debt Issuance Date

Various

^[13]

Various

Percentage of debt instrument interest rate stated

$ 227,783

$ 226,847

$ 227,783

$ 226,847

^[8]

Various

Capital Lease Obligations and Other [Member] | Maximum [Member]

Fixed Rate Securitized Debt 2010 Tower Revenue Notes [Member]

10.00%

Interest rate, increase (decrease)

$ 2,300,000

5.00%

Variable Rate Revolver [Member]

2015 Tower Revenue Notes 3.222% due 2042 [Member] | Securitized Debt [Member]

Availability on revolver

2,500,000

$ 2,500,000

2015 Tower Revenue Notes 3.663% due 2045 [Member] | Securitized Debt [Member]

300,000

$ 700,000

[1]	Exclusive of accrued interest.
[2]	Exclusive of accrued interest
[3]	The sum of quarterly information may not agree to year to date information due to rounding.
[4]	Inclusive of $33.8 million related to the write off of deferred financing costs
[5]	Inclusive of $4.2 million related to the write off of deferred financing costs, premiums and discounts.
[6]	The losses related to write off of deferred financing costs.
[7]	As of December 31, 2017, the undrawn availability under the 2016 Revolver was $2.5 billion.
[8]	Represents the weighted-average stated interest rate.
[9]	The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.125% to 2.000%, based on the Company's senior unsecured debt rating. The Company pays a commitment fee of approximately 0.200% per annum on the undrawn available amount under the 2016 Revolver.
[10]	(d)The Secured Notes, Series 2009-1, Class A-1 and Secured Notes, Series 2009-1, Class A-2 are collectively referred to herein as "2009 Securitized Notes."
[11]	(e)The Tower Revenue Notes, Series 2010-3 ("January 2010 Tower Revenue Notes"), Tower Revenue Notes, Series 2010-6 ("August 2010 Tower Revenue Notes") and Tower Revenue Notes, Series 2015-1 and 2015-2 ("May 2015 Tower Revenue Notes") are collectively referred to herein as "Tower Revenue Notes."
[12]	If the respective series of Tower Revenue Notes are not paid in full on or prior to an applicable anticipated repayment date, then Excess Cash Flow (as defined in the indenture) of the issuers of such notes will be used to repay principal of the applicable series and class of the Tower Revenue Notes, and additional interest (of an additional approximately 5% per annum) will accrue on the respective Tower Revenue Notes. As of December 31, 2017, the Tower Revenue Notes have principal amounts of $2.3 billion, $300.0 million and $700.0 million, with anticipated repayment dates in 2020, 2022 and 2025, respectively.
[13]	The Company's capital leases and other obligations relate to land, fiber, vehicles, and other assets and bear interest rates ranging up to 10% and mature in periods ranging from less than one year to approximately 30 years.

Debt and Other Obligations (Textuals) (Details) - USD ($)

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2012

Borrowings under revolving credit facility

$ 16,159,620,000

$ 12,171,142,000

2,820,000,000

3,440,000,000

$ 1,790,000,000

$ 1,650,000,000

Jan. 01, 2023

Principal balance outstanding on debt instruments

4,026,390,000

1,069,361,000

16,261,760,000

Cash and equivalents

$ 314,094,000

567,599,000

Oct. 01, 2012

Debt Instrument, Covenant Description

5.30%

7.0 to 1.0

Variable Rate Revolver [Member]

Fixed Rate Securitized Debt 2010 Tower Revenue Notes [Member]

Availability on revolver

$ 2,500,000,000

Interest rate, increase (decrease)

5.00%

Capital Lease Obligations and Other [Member]

$ 2,300,000,000

Contractual maturity date, start

$ 227,783,000

226,847,000

1 year

Contractual maturity date, end

30 years

2016 Revolver [Member]

Line of Credit Facility, Maximum Borrowing Capacity

$ 3,500,000,000

Line of Credit Facility, Change in Borrowing Capacity

Aug. 01, 2017

$ 1,000,000,000

Aug. 01, 2022

2016 Term Loan A [Member]

500,000,000

Feb. 01, 2017

Securitized Debt [Member]

Jan. 01, 2022

Securitized Debt [Member] | 2015 Tower Revenue Notes 3.222% due 2042 [Member]

$ 3,332,309,000

3,345,805,000

Securitized Debt [Member] | 2015 Tower Revenue Notes 3.663% due 2045 [Member]

300,000,000

700,000,000

Bank Debt [Member]

Bank Debt [Member] | 2016 Revolver [Member]

3,376,588,000

1,954,173,000

Line of Credit Facility, Maximum Borrowing Capacity

2,500,000,000

$ 980,000,000

^[1]

Jan. 01, 2016

Bank Debt [Member] | 2016 Term Loan A [Member]

^[2],[3]

2.60%

$ 2,396,588,000

1,954,173,000

2,000,000,000

Jan. 01, 2016

January 2010 Tower Revenue Notes [Member]

^[2],[3]

2.60%

High Yield Bonds [Member]

Repayments of Debt

$ 300,000,000.0

High Yield Bonds [Member] | May 2016 Senior Unsecured Notes [Member]

$ 9,222,940,000

6,644,317,000

$ 1,000,000,000

High Yield Bonds [Member] | 4.875% Senior Notes [Member]

May 01, 2016

842,090,000

$ 840,322,000

$ 850,000,000

Apr. 01, 2022

Apr. 01, 2014

High Yield Bonds [Member] | 4.000% Senior Unsecured Notes [Member]

4.90%

^[2]

4.90%

$ 493,833,000

$ 500,000,000

Mar. 01, 2027

Feb. 01, 2017

High Yield Bonds [Member] | 2016 Senior Unsecured Notes [Domain]

^[2]

4.00%

$ 1,500,000,000

High Yield Bonds [Member] | 3.400% Senior Notes [Member]

Feb. 01, 2016

$ 849,859,000

$ 849,698,000

$ 250,000,000

Feb. 01, 2016

High Yield Bonds [Member] | 3.700% Senior Notes [Member]

3.40%

^[2]

3.40%

$ 742,727,000

$ 741,908,000

$ 750,000,000

Jun. 01, 2026

May 01, 2016

High Yield Bonds [Member] | 4.450% Senior Notes [Member]

3.70%

^[2]

3.70%

$ 891,145,000

$ 890,118,000

$ 900,000,000

Feb. 01, 2026

Feb. 01, 2016

High Yield Bonds [Member] | 4.750% Senior Unsecured Notes [Member] [Member]

4.50%

^[2]

4.50%

$ 343,209,000

$ 0

$ 350,000,000

May 01, 2047

May 01, 2017

High Yield Bonds [Member] | August 2017 Senior Notes [Member]

^[2]

4.80%

$ 1,750,000,000

High Yield Bonds [Member] | August 2017 Senior Unsecured 3.200% Notes [Member]

Aug. 01, 2017

$ 750,000,000

Sep. 01, 2024

High Yield Bonds [Member] | August 2017 Senior Unsecured 3.650% Notes [Member]

3.20%

$ 1,000,000,000

Sep. 01, 2027

2.250% Senior Notes [Member] | September 2016 Senior Unsecured Notes [Member]

3.70%

$ 700,000,000

Sep. 01, 2021

Sep. 01, 2016

2.381% Secured Notes [Member]

2.30%

2.381% Secured Notes [Member] | September 2016 Senior Unsecured Notes [Member]

$ 500,000,000

Issuance of debt obligation [Member] | 4.875% Senior Notes [Member]

2.40%

Repayments of Debt

$ 500,000,000.0

Proceeds from Issuance of Debt

$ 839,000,000

2012 Revolver [Member]

2012 secured notes tranche B [Member]

Maximum [Member] | Variable Rate Revolver 2012 [Member]

$ 1,000,000,000

Maximum [Member] | Capital Lease Obligations and Other [Member]

2.00%

Minimum [Member] | Variable Rate Revolver 2012 [Member]

10.00%

August 2010 Tower Revenue Notes ARD [Domain] | Securitized Debt [Member] | Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 5 [Member]

1.10%

Collateral Pledged [Member]

$ 250,000,000

Debt Instrument, PPE Collaterized Amount

$ 1,100,000,000

Additional Principal Incurred [Member] | 2016 Term Loan A [Member]

Additional Principal Incurred [Member] | Bank Debt [Member] | Senior Unsecured 364-Day Revolving Credit Facility [Domain]

$ 500,000,000

Line of Credit Facility, Maximum Borrowing Capacity

1,000,000,000

February 2016 Senior Note Upsizing [Member] | High Yield Bonds [Member] | 3.400% Senior Notes [Member]

$ 600,000,000

3.40%

[1]	As of December 31, 2017, the undrawn availability under the 2016 Revolver was $2.5 billion.
[2]	Represents the weighted-average stated interest rate.
[3]	The 2016 Revolver and senior unsecured term loan A facility ("2016 Term Loan A") bear interest at a rate per annum equal to LIBOR plus a credit spread ranging from 1.125% to 2.000%, based on the Company's senior unsecured debt rating. The Company pays a commitment fee of approximately 0.200% per annum on the undrawn available amount under the 2016 Revolver.

Debt and Other Obligations (Scheduled Contractual Maturities) (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
2018	$ 116,045
2019	167,458
2020	155,051
2021	1,824,568
2022	3,701,737
Thereafter	10,296,901
Total Cash Obligations	16,261,760
Unamortized Discounts	(102,140)
Total Debt and Other Obligations Outstanding	$ 16,159,620

Debt and Other Obligations (Debt Purchases and Repayments) (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

^[3]

Sep. 30, 2017

^[3]

Jun. 30, 2017

^[3]

Mar. 31, 2017

^[3]

Dec. 31, 2016

^[3]

Sep. 30, 2016

^[3]

Jun. 30, 2016

^[3]

Mar. 31, 2016

^[3]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

$ (4,026,390)

$ (1,069,361)

Gains (losses) on retirement of long-term obligations

4,044,834

^[1]

1,069,337

^[2]

$ 0

$ (3,525)

$ 0

$ (10,274)

$ (11,467)

$ (30,550)

$ (3,525)

(52,291)

^[4]

(4,157)

^[5]

Write-off of deferred financing costs and discounts

33,800

4,200

Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 4 [Domain]

(250,000)

Gains (losses) on retirement of long-term obligations

^[2]

250,000

^[5]

(159)

2016 Term Loan A [Member]

Gains (losses) on retirement of long-term obligations

^[6]

$ (3,525)

Variable Rate 2012 Term Loans Tranche A [Member]

(629,375)

Gains (losses) on retirement of long-term obligations

^[1]

629,375

^[4]

(1,498)

August 2010 Tower Revenue Notes [Member]

Gains (losses) on retirement of long-term obligations

^[1]

^[4]

(1,930)

WCP Securitized Notes [Member]

(252,830)

Gains (losses) on retirement of long-term obligations

^[2]

252,830

^[5]

2,105

Variable Rate 2012 Term Loans Tranche B [Member]

(2,247,015)

(564,137)

Gains (losses) on retirement of long-term obligations

2,247,015

^[1]

564,137

^[2]

(27,122)

^[4]

(6,127)

^[5]

Fixed Rate Securitized Debt January 2010 Tower Revenue Notes 2 [Member]

(350,000)

Gains (losses) on retirement of long-term obligations

^[1]

352,796

^[4]

(3,338)

Fixed Rate Securitized Debt August 2010 Tower Revenue Notes 5 [Member]

(300,000)

Gains (losses) on retirement of long-term obligations

^[1]

307,176

^[4]

(8,129)

Fixed Rate High Yield Bonds 7Point125 Percent Senior Notes [Member]

(500,000)

Gains (losses) on retirement of long-term obligations

^[1]

508,472

^[4]

$ (10,274)

Other Debt Instruments [Domain]

(2,394)

Gains (losses) on retirement of long-term obligations

^[2]

2,370

^[5]

$ 24

[1]	Exclusive of accrued interest.
[2]	Exclusive of accrued interest
[3]	The sum of quarterly information may not agree to year to date information due to rounding.
[4]	Inclusive of $33.8 million related to the write off of deferred financing costs
[5]	Inclusive of $4.2 million related to the write off of deferred financing costs, premiums and discounts.
[6]	The losses related to write off of deferred financing costs.

Swaps Foreign Currency Swaps (Details) AUD in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 AUD	Dec. 31, 2015 AUD
Derivative [Line Items]
Gains (Losses) on Settled Swaps \| $	$ (328)	$ (2,608)	$ 54,475
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments \| $			$ 65,200
Foreign Exchange [Member]
Derivative [Line Items]
Derivative, Notional Amount					AUD 1,400,000
May 2015 cash receipt from sale of CCAL [Domain]
Derivative [Line Items]
Derivative, Notional Amount				AUD 1,400,000
Derivative, Inception Date			May 14, 2015
Derivative, Maturity Date			Jun. 12, 2015
Derivative, Currency Sold			US Dollar
Derivative, Currency Bought			Australian Dollar
Derivative, Forward Exchange Rate					0.8072
Installment payment from Buyer [Domain]
Derivative [Line Items]
Derivative, Notional Amount				AUD 155,000	AUD 155,000
Derivative, Inception Date		May 14, 2015
Derivative, Maturity Date		Jan. 04, 2016
Derivative, Currency Sold		US Dollar
Derivative, Currency Bought		Australian Dollar
Derivative, Forward Exchange Rate		0.7984

Fair Value Disclosures (Estimated Fair Values and Carrying Amounts of Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents, carrying value	$ 314,094	$ 567,599
Cash and cash equivalents, fair value	314,094	567,599
Restricted cash, carrying value	126,065	129,547
Restricted cash, fair value	126,065	129,547
Debt and other obligations, carrying amount	16,159,620	12,171,142
Debt and other obligations, fair value	$ 16,643,725	$ 12,660,013

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation allowance, increase (decrease)	$ (21)	$ 21	$ (3,000)
Federal tax benefits	2,816	$ 227	$ (495)
Stock Compensation Plan [Member]
Operating Loss Carryforwards	237,000
U.S. Federal [Member]
Operating Loss Carryforwards	1,500,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	600,000
Foreign [Member]
Operating Loss Carryforwards	$ 53,200
Maximum [Member] \| U.S. Federal [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
Maximum [Member] \| State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2036
Maximum [Member] \| Foreign [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2037
Minimum [Member] \| U.S. Federal [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2024
Minimum [Member] \| State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2018
Minimum [Member] \| Foreign [Member]
Operating Loss Carryforwards, Expiration Date	Dec. 31, 2022

Income Taxes (Income (Loss) from Continuing Operations before Income Taxes) (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Income (loss) from continuing operations before income taxes

Domestic

$ 450,771

$ 349,041

$ 461,293

Foreign

^[1]

19,822

24,813

12,536

$ 470,593

$ 373,854

$ 473,829

[1]	Inclusive of income (loss) before income taxes from Puerto Rico.

Income Taxes (Benefit (Provision) for Income Taxes) (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

^[1]

Sep. 30, 2017

^[1]

Jun. 30, 2017

^[1]

Mar. 31, 2017

^[1]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Current Federal

$ (2,816)

$ (227)

$ 495

Current Foreign

(6,050)

(6,820)

(5,675)

Current State

(2,289)

(1,231)

(3,981)

Total current

(11,155)

(8,278)

(9,161)

Deferred Federal

(17,743)

(7,968)

44,716

Deferred Foreign

2,883

(601)

(1,048)

Deferred State

(28)

(34)

16,950

Total deferred

(14,888)

(8,603)

60,618

Tax adjustment related to the small cell REIT conversion

$ (14,753)

$ (2,383)

$ (4,538)

$ (4,369)

(26,043)

(16,881)

51,457

^[2]

$ 0

$ 33,759

[1]	The sum of quarterly information may not agree to year to date information due to rounding.
[2]	During the fourth quarter of 2015, the Company de-recognized the net deferred tax liabilities related to the Company's small cells previously included in one or more TRSs in conjunction with the inclusion of small cells in the REIT in January 2016.

Income Taxes Income Taxes Effective Income Tax Rate Reconciliation (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

Sep. 30, 2017

^[3]

Jun. 30, 2017

^[3]

Mar. 31, 2017

^[3]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount

$ (164,707)

$ (130,849)

$ (165,840)

Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount

(430)

1,215

(527)

Tax adjustment related to REIT operations

158,812

121,092

(186,649)

Tax adjustment related to the small cell REIT conversion

^[1]

33,759

Losses for which no tax benefit was recognized

(42)

(43)

(414)

Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount

(21)

3,000

Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount

(2,115)

(1,085)

1,210

Foreign Income Tax Expense (Benefit), Continuing Operations

(3,168)

(7,421)

(6,723)

Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount

^[2]

(14,628)

Effective Income Tax Rate Reconciliation, Other Adjustments, Amount

214

231

343

Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount

$ (14,753)

^[3]

$ (2,383)

$ (4,538)

$ (4,369)

(26,043)

$ (16,881)

$ 51,457

^[2]

16,800

Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax

$ 2,200

[1]	During the fourth quarter of 2015, the Company de-recognized the net deferred tax liabilities related to the Company's small cells previously included in one or more TRSs in conjunction with the inclusion of small cells in the REIT in January 2016.
[2]	Pursuant to the Tax Cuts and Jobs Act, which was signed into law in December 2017, the Company was required to write down its net federal deferred tax asset in the amount of $16.8 million as a result of the reduction in the federal corporate tax rate offset by a benefit of $2.2 million related to the refund of the Company's alternative minimum tax credit carryforward.
[3]	The sum of quarterly information may not agree to year to date information due to rounding.

Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property and equipment	$ 4,940	$ 3,945
Deferred site rental receivable	6,907	6,192
Deferred Tax Liabilities, Gross	11,847	10,137
Deferred Tax Assets, Goodwill and Intangible Assets	4,460	22,377
Net operating loss carryforwards	20,800	21,143
Deferred ground lease payable	2,060	1,646
Accrued liabilities	5,161	5,511
Receivable allowance	317	383
Other	1,431	1,726
Valuation allowance, asset	(1,172)	(6,627)
Total deferred income tax assets, net	33,057	46,159
Deferred Tax Assets, Net	21,210	36,022
Domestic Tax Authority [Member]
Valuation allowance, asset	0	(21)
Deferred Tax Assets, Net	25,260	42,927
State and Local Jurisdiction [Member]
Valuation allowance, asset	0	0
Deferred Tax Assets, Net	1,142	1,170
Foreign Tax Authority [Member]
Valuation allowance, asset	$ (1,172)	$ (6,606)

Income Taxes (Jurisdictional Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Taxes (Jurisdictional components of deferred taxes)
Gross, asset	$ 22,382	$ 42,649
Valuation allowance, asset	(1,172)	(6,627)
Net deferred income tax assets (liabilities)	21,210	36,022
Deferred Tax Liabilities, Net		36,022
U.S. Federal [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	1,500,000
Gross, asset	25,260	42,948
Valuation allowance, asset	0	(21)
Net deferred income tax assets (liabilities)	25,260	42,927
State and Local Jurisdiction [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	600,000
Gross, asset	1,142	1,170
Valuation allowance, asset	0	0
Net deferred income tax assets (liabilities)	1,142	1,170
Foreign [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	53,200
Gross, asset	(4,020)	(1,469)
Valuation allowance, asset	(1,172)	(6,606)
Deferred Tax Liabilities, Net	(5,192)	$ (8,075)
Stock Compensation Plan [Member]
Income Taxes (Jurisdictional components of deferred taxes)
Operating Loss Carryforwards	$ 237,000

Income Taxes Income Taxes (Unrecognized Tax Benefits) (Details) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 3,080	$ 6,770
Additions based on current year tax positions	0	116
Reductions as a result of the lapse of statute limitations	(3,080)	(3,806)
Balance at end of year	$ 0	$ 3,080

Stockholders' Equity (Details)

3 Months Ended

12 Months Ended

Dec. 31, 2017

USD ($)

$ / shares

Sep. 30, 2017

USD ($)

$ / shares

Jun. 30, 2017

USD ($)

$ / shares

Mar. 31, 2017

USD ($)

$ / shares

Dec. 31, 2017

USD ($)

$ / shares

Dec. 31, 2016

USD ($)

Dec. 31, 2015

USD ($)

Vesting Period

3 years

Preferred Stock, Liquidation Preference, Value

$ 1,650,000

$ 0

Dividends, Common Stock, Cash

$ 428,800,000

^[1]

$ 389,600,000

^[1]

$ 350,300,000

^[1]

$ 343,300,000

^[1]

$ 1,512,034,000

1,244,423,000

Conversion factor, Preferred Stock | shares

$ 1,325,865,000

1.188

6.875% Mandatory Convertible Preferred Stock, Par or Stated Value Per Share | $ / shares

$ 0.01

Purchases of common stock, value

$ 23,300,000

$ 24,900,000

$ 29,700,000

At the Market Stock Offering Program, aggregate value of common stock

$ 500,000,000

Life to Date Shares Sold Under ATM | shares

3,800,000

Life to Date Net Proceeds Under ATM

$ 323,800,000

Life to Date Fees Under ATM

3,300,000

Availability Under ATM

$ 150,000,000

150,000,000

Common Stock, Dividends, Per Share, Cash Paid | $ / shares

$ 1.05

$ 0.950

Preferred Stock, Dividends, Per Share, Cash Paid | $ / shares

$ 17.1875

$ 18.142

Dividends, Preferred Stock, Cash

$ 28,400,000

$ 29,900,000

43,988,000

Net proceeds from issuance of preferred stock

$ 1,607,759,000

$ 0

Minimum [Member]

Conversion factor, Preferred Stock | shares

8.6806

Maximum [Member]

Conversion factor, Preferred Stock | shares

10.4167

Preferred Stock [Member]

Dividends Payable, Date Declared

Dec. 15, 2017

Sep. 21, 2017

Dividends Payable, Date of Record

Jan. 15, 2018

Oct. 15, 2017

Dividends Payable, Date to be Paid

Feb. 01, 2018

Nov. 01, 2017

Common Stock [Member]

Dividends Payable, Date Declared

Oct. 15, 2017

Aug. 03, 2017

May 18, 2017

Feb. 17, 2017

Dividends Payable, Date of Record

Dec. 15, 2017

Sep. 15, 2017

Jun. 16, 2017

Mar. 17, 2017

Dividends Payable, Date to be Paid

Dec. 29, 2017

Sep. 29, 2017

Jun. 30, 2017

Mar. 31, 2017

November 2016 Equity Offering [Member]

Preferred Stock, Liquidation Preference, Value

$ 1,000,000,000

Preferred Stock [Member]

$ 1,000

Preferred Stock, Redemption Date

Aug. 01, 2020

Preferred Stock, Dividend Rate, Percentage

6.875%

Preferred Stock [Member] | July 2017 Equity Offering [Member]

Stock Issued During Period, Shares, New Issues | shares

1,650,000

Sale of Stock, Transaction Date

Jul. 26, 2017

Preferred Stock, Dividend Rate, Percentage

6.875%

Preferred Stock, Per Share Sales Price | $ / shares

$ 1,000

Net proceeds from issuance of preferred stock

$ 1,600,000,000

Common Stock [Member]

Stock Issued During Period, Shares, New Issues | shares

45,142,300

15,178,064

Purchases of common stock, shares | shares

$ 152,000

(259,331)

(289,531)

(336,526)

Common Stock [Member] | May 2017 Equity Offering [Member]

Stock Issued During Period, Shares, New Issues | shares

4,750,000

Sale of Stock, Transaction Date

$ 442,000,000

May 01, 2017

Common Stock [Member] | July 2017 Equity Offering [Member]

Stock Issued During Period, Shares, New Issues | shares

40,150,000

Sale of Stock, Transaction Date

$ 3,800,000,000

Jul. 26, 2017

Common Stock [Member] | November 2016 Equity Offering [Member]

Stock Issued During Period, Shares, New Issues | shares

11,400,000

Preferred Stock [Member] | Preferred Stock [Member]

Conversion of Stock, Shares Converted | shares

9,800,000

Preferred Stock [Member] | Common Stock [Member]

Conversion of Stock, Shares Issued | shares

11,600,000

[1]	Inclusive of dividends accrued for holders of unvested RSUs, which will be paid when and if the RSUs vest

Stockholders' Equity Tax Treatment of Dividends Paid (Details) - $ / shares	3 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid	$ 17.1875	$ 18.142
Common Stock, Dividends, Per Share, Cash Paid	$ 1.05	$ 0.950	$ 0.950	$ 0.950
Preferred Stock [Member]
Class of Stock [Line Items]
Payment Date	Feb. 01, 2018	Nov. 01, 2017
Common Stock [Member]
Class of Stock [Line Items]
Payment Date	Dec. 29, 2017	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017
Common Stock [Member]
Class of Stock [Line Items]
Non-Taxable Distribution	$ 0.000	$ 0.000	$ 0.000	$ 0.000
Ordinary Taxable Dividend Per Share [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid		18.142
Common Stock, Dividends, Per Share, Cash Paid	1.050	0.950	0.950	0.950
Qualified Taxable Dividend Per Share [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid		6.629
Common Stock, Dividends, Per Share, Cash Paid	0.384	0.347	0.347	0.347
Long-Term Capital Gain Distribution Per Share [Member]
Class of Stock [Line Items]
Preferred Stock, Dividends, Per Share, Cash Paid		0.000
Common Stock, Dividends, Per Share, Cash Paid	$ 0.000	$ 0.000	$ 0.000	$ 0.000

Stock-based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	11.2
Vesting Period	3 years
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for future issuance (in shares)	3.0
Shares granted, number of shares	1.3	1.3
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, weighted-average grant-date fair value (in dollars per share)	$ 73.52	$ 68.53	$ 69.96
Weighted-average requisite service period (years)	2 years 6 months
Restricted stock or unit expense	$ 88.7	$ 76.3	$ 57.1
Performance Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, number of shares	0.6
Time Vesting Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted, number of shares	0.7
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost not yet recognized	$ 72.9
Period for recognition	1 year

Stock-based Compensation (Summary of Restricted Stock Awards Activity) (Details) - Restricted Stock Units (RSUs) [Member] - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	1,300	1,300
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	1,359
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	747
Shares outstanding at the beginning of the year, number of shares	2,677
Shares outstanding at the end of year, number of shares	2,968	2,677
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	(321)

Stock-based Compensation (Summary of the Assumptions Used in the Monte Carlo Simulation to Determine the Grant-Date Fair Value) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation [Abstract]
Risk-free rate	1.50%	0.90%	1.00%
Expected volatility	18.00%	19.00%	19.00%
Expected dividend rate	4.40%	4.24%	4.00%

Stock-based Compensation (Summary of Restricted Stock Awards Vested) (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total shares vested	747	828	946
Fair value on vesting date	$ 67,241	$ 71,325	$ 83,244
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	2,968	2,677
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	1,359
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	747
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares	321

Stock-based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 96,435	$ 96,538	$ 67,148
Site Rental Cost of Operations [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	14,942	14,371	8,969
Network Services and Other Costs of Operations [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	4,961	7,717	5,370
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 76,532	$ 74,450	$ 52,809

Leases (Details) - USD ($) $ in Thousands	12 Months Ended
Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property Subject to or Available for Operating Lease [Line Items]
Weighted average remaining term of tenant leases	6 years
Maximum Current Term	20 years
Tenant Leases 2017	$ 3,401,845
Tenant Leases 2018	3,277,019
Tenant Leases 2019	3,160,514
Tenant Leases 2020	3,028,825
Tenant Leases 2021	2,805,519
Tenant Leases thereafter	5,628,294
Total tenant leases	$ 21,302,016
Percentage of wireless infrastructure that has non-cancelable operating leases	76.00%
Operating Leases, Owned Land Under Tower, Expiration Term	20 years
Operating Leases, Leased Land Under Tower, Expiration Term	10 years
Operating leases 2017	$ 635,321
Operating leases 2018	632,775
Operating leases 2019	622,587
Operating leases 2020	617,951
Operating leases 2021	609,796
Operating leases thereafter	7,941,187
Total operating leases	11,059,617
Rental expense from operating leases	710,200	$ 677,900	$ 657,100
Contingent rental payments	$ 100,100	$ 96,900	$ 91,800
Greater than 10 Years, Inclusive of Renewals at the Company's Option [Member]
Property Subject to or Available for Operating Lease [Line Items]
Percentage of site rental gross margin that is derived from towers where the lease for the land has a final expiration date	90.00%
Greater than 20 Years, Inclusive of Renewals at the Company's Option [Member]
Property Subject to or Available for Operating Lease [Line Items]
Percentage of site rental gross margin that is derived from towers where the lease for the land has a final expiration date	75.00%

Operating Segments and Concentrations of Credit Risk (Major Customers) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allocated Share-based Compensation Expense	$ 96,435	$ 96,538	$ 67,148
Concentration Risk, Percentage	86.00%	88.00%	89.00%
AT&T [Member]
Concentration Risk, Percentage	25.00%	27.00%	27.00%
Sprint [Member]
Concentration Risk, Percentage	17.00%	16.00%	19.00%
Verizon Wireless [Member]
Concentration Risk, Percentage	22.00%	22.00%	21.00%
T-Mobile [Member]
Concentration Risk, Percentage	22.00%	23.00%	22.00%
Selling, General and Administrative Expenses [Member]
Allocated Share-based Compensation Expense	$ 76,500	$ 74,500	$ 52,800
Cost of Sales [Member]
Allocated Share-based Compensation Expense	$ 19,900	$ 22,100	$ 14,300

Operating Segments and Concentrations of Credit Risk Operating Segment Results (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Tower Count	40,000
Segment Site Rental Revenues	$ 3,669,191	$ 3,233,307	$ 3,018,413
Segment Network Services and Other Revenues	686,414	687,918	645,438
Segment Revenues	4,355,605	3,921,225	3,663,851
Segment Site Rental Cost of Operations	1,108,854	987,668	934,370
Segment Network Services and Other Cost of Operations	414,825	409,454	352,187
Segment Cost of Operations	1,523,679	1,397,122	1,286,557
Segment site rental gross margin	2,560,337	2,245,639	2,084,043
Segment network services gross margin	271,589	278,464	293,251
Segment General and Administrative Expenses	350,165	296,580	258,111
Segment Operating Profit	2,481,761	2,227,523	2,119,183
Allocated Share-based Compensation Expense	96,435	96,538	67,148
Amortization of prepaid lease purchase price adjustments	20,100	21,300	20,500
Depreciation, Amortization and Accretion, Net	1,242,408	1,108,551	1,036,178
Interest expense and amortization of deferred financing costs	590,682	515,032	527,128
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes	81,643	133,548	14,900
Income (Loss) from Continuing Operations Before Income Taxes	470,593	373,854	473,829
Capital Expenditures	1,228,071	873,883	908,892
Assets	32,229,570	22,675,092	21,936,966
Goodwill	$ 10,021,468	5,757,676	5,513,551
Fiber Miles	60,000
Towers [Member]
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	$ 2,899,554	2,830,708	2,734,045
Segment Network Services and Other Revenues	636,532	603,689	591,655
Segment Revenues	3,536,086	3,434,397	3,325,700
Segment Site Rental Cost of Operations	844,795	840,209	827,175
Segment Network Services and Other Cost of Operations	374,134	344,595	309,025
Segment Cost of Operations	1,218,929	1,184,804	1,136,200
Segment site rental gross margin	2,054,759	1,990,499	1,906,870
Segment network services gross margin	262,398	259,094	282,630
Segment General and Administrative Expenses	93,662	92,903	91,899
Segment Operating Profit	2,223,495	2,156,690	2,097,601
Capital Expenditures	418,476	429,526	564,753
Assets	17,940,893	18,394,572	17,974,847
Goodwill	5,127,259	5,114,639	4,863,847
Small Cells [Member]
Segment Reporting Information [Line Items]
Segment Site Rental Revenues	769,637	402,599	284,368
Segment Network Services and Other Revenues	49,882	84,229	53,783
Segment Revenues	819,519	486,828	338,151
Segment Site Rental Cost of Operations	264,059	147,459	107,195
Segment Network Services and Other Cost of Operations	40,691	64,859	43,162
Segment Cost of Operations	304,750	212,318	150,357
Segment site rental gross margin	505,578	255,140	177,173
Segment network services gross margin	9,191	19,370	10,621
Segment General and Administrative Expenses	89,048	60,676	38,379
Segment Operating Profit	425,721	213,834	149,415
Capital Expenditures	782,409	409,710	314,882
Assets	13,669,636	3,440,600	3,511,956
Goodwill	4,894,209	643,037	649,704
Other [Member]
Segment Reporting Information [Line Items]
Segment General and Administrative Expenses	167,455	143,001	127,833
Segment Operating Profit	(167,455)	(143,001)	(127,833)
Allocated Share-based Compensation Expense	96,435	96,538	67,148
Depreciation, Amortization and Accretion, Net	1,242,408	1,108,551	1,036,178
Interest expense and amortization of deferred financing costs	590,682	515,032	527,128
Other income (expenses) to reconcile to income (loss) from continuing operations before income taxes	81,643	133,548	14,900
Capital Expenditures	27,186	34,647	29,257
Assets	619,041	839,920	450,163
Goodwill	0	0	0
Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Allocated Share-based Compensation Expense	76,500	74,500	52,800
Cost of Sales [Member]
Segment Reporting Information [Line Items]
Allocated Share-based Compensation Expense	$ 19,900	$ 22,100	$ 14,300

Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Information [Line Items]
Interest paid	$ 546,543	$ 470,655	$ 489,970
Income taxes paid (refund)	16,427	13,821	28,771
Increase (Decrease) in accounts payable for purchases of property and equipment	2,279	17,922	(7,042)
Purchase of property and equipment under capital leases and installment purchases	31,999	52,322	60,270
Installment payment receivable for sale of subsidiary	0	0	117,384
Preferred Stock Dividends Accrued but not Paid	$ 28,359	$ 0	$ 10,997

Quarterly Financial Information (Unaudited) (Details) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2017

^[1]

Sep. 30, 2017

^[1]

Jun. 30, 2017

^[1]

Mar. 31, 2017

^[1]

Dec. 31, 2016

^[1]

Sep. 30, 2016

^[1]

Jun. 30, 2016

^[1]

Mar. 31, 2016

^[1]

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Selected Quarterly Financial Information [Abstract]

Net revenues

$ 1,238,090

$ 1,063,238

$ 1,038,335

$ 1,015,942

$ 1,032,416

$ 992,016

$ 962,409

$ 934,384

$ 4,355,605

$ 3,921,225

$ 3,663,851

Operating income (loss)

268,429

260,567

258,500

256,549

262,038

244,254

231,185

211,739

1,044,045

949,216

946,180

Gains (losses) on retirement of long-term obligations

(14,753)

(2,383)

(4,538)

(4,369)

(26,043)

(16,881)

51,457

(3,525)

(10,274)

(11,467)

(30,550)

(3,525)

(52,291)

^[2]

(4,157)

^[3]

Net income (loss) attributable to CCIC stockholders

$ 98,104

$ 115,194

$ 112,114

$ 119,138

$ 124,709

$ 98,366

$ 86,058

$ 47,840

$ 444,550

$ 356,973

$ 1,520,992

Net income (loss) attributable to CCIC common stockholders, per common share:

$ 0.17

$ 0.22

$ 0.31

$ 0.33

$ 0.35

$ 0.26

$ 0.22

$ 0.11

$ 1.01

$ 0.95

$ 4.44