Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Entity Registrant Name	AMERICAN TOWER CORP /MA/
Entity Central Index Key	0001053507
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		427,195,037
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 47.9

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
CURRENT ASSETS:
Cash and cash equivalents	$ 787,161	$ 320,686
Restricted cash	149,281	142,193
Short-term investments	4,026	0
Accounts receivable, net	308,369	227,354
Prepaid and other current assets	441,033	306,235
Total current assets	1,689,870	996,468
PROPERTY AND EQUIPMENT, net	10,517,258	9,866,424
GOODWILL	5,070,680	4,091,805
OTHER INTANGIBLE ASSETS, net	11,274,611	9,837,876
DEFERRED TAX ASSET	195,678	212,041
DEFERRED RENT ASSET	1,289,530	1,166,755
NOTES RECEIVABLE AND OTHER NON-CURRENT ASSETS	841,523	732,903
TOTAL	30,879,150	26,904,272
CURRENT LIABILITIES:
Accounts payable	118,666	96,714
Accrued expenses	620,563	516,413
Distributions payable	250,550	210,027
Accrued interest	157,297	115,672
Current portion of long-term obligations	238,806	50,202
Unearned revenue	245,387	211,001
Total current liabilities	1,631,269	1,200,029
LONG-TERM OBLIGATIONS	18,294,659	17,068,807
ASSET RETIREMENT OBLIGATIONS	965,507	856,936
DEFERRED TAX LIABILITY	777,572	106,333
OTHER NON-CURRENT LIABILITIES	1,142,723	959,349
Total liabilities	22,811,730	20,191,454
COMMITMENTS AND CONTINGENCIES
REDEEMABLE NONCONTROLLING INTERESTS	1,091,220	0
EQUITY:
Common stock: $.01 par value; 1,000,000,000 shares authorized; 429,912,536 and 426,695,279 shares issued; and 427,102,510 and 423,885,253 shares outstanding, respectively	4,299	4,267
Additional paid-in capital	10,043,559	9,690,609
Distributions in excess of earnings	(1,076,965)	(998,535)
Accumulated other comprehensive loss	(1,999,332)	(1,836,996)
Treasury stock (2,810,026 shares at cost)	(207,740)	(207,740)
Total American Tower Corporation equity	6,763,895	6,651,679
Noncontrolling interests	212,305	61,139
Total equity	6,976,200	6,712,818
TOTAL	30,879,150	26,904,272
Preferred stock \| Convertible Preferred Stock Subject to Mandatory Redemption \| Series A Preferred Stock
EQUITY:
Preferred stock: $.01 par value: 20,000,000 authorized: 5.25%, Series A, 6,000,000 shares issued and outstanding; aggregate liquidation value of $600,000 - 5.50% Series B, 1,375,000 shares issued and outstanding, respectively; aggregate liquidation value of $1,375,000	60	60
Total equity	60	60
Preferred stock \| Convertible Preferred Stock Subject to Mandatory Redemption \| Series B Preferred Stock
EQUITY:
Preferred stock: $.01 par value: 20,000,000 authorized: 5.25%, Series A, 6,000,000 shares issued and outstanding; aggregate liquidation value of $600,000 - 5.50% Series B, 1,375,000 shares issued and outstanding, respectively; aggregate liquidation value of $1,375,000	14	14
Total equity	$ 14	$ 14

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	12 Months Ended
CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	429,912,536	426,695,279
Common stock, shares outstanding	427,102,510	423,885,253
Treasury stock, shares	2,810,026	2,810,026
Preferred stock \| Convertible Preferred Stock Subject to Mandatory Redemption
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Preferred stock \| Series A Preferred Stock \| Convertible Preferred Stock Subject to Mandatory Redemption
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, dividend rate, percentage	5.25%	5.25%
Preferred stock, shares issued	6,000,000	6,000,000
Preferred stock, shares outstanding	6,000,000	6,000,000
Preferred stock, aggregate liquidation value	$ 600,000	$ 600,000
Preferred stock \| Series B Preferred Stock \| Convertible Preferred Stock Subject to Mandatory Redemption
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, dividend rate, percentage	5.50%
Preferred stock, shares issued	1,375,000
Preferred stock, shares outstanding	1,375,000
Preferred stock, aggregate liquidation value	$ 1,375,000

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
REVENUES:
Property	$ 5,713,126	$ 4,680,388	$ 4,006,854
Services	72,542	91,128	93,194
Total operating revenues	5,785,668	4,771,516	4,100,048
OPERATING EXPENSES:
Property (including stock-based compensation expense of $1,750, $1,614 and $1,397, respectively)	1,762,694	1,275,436	1,056,177
Services (including stock-based compensation expense of $688, $439 and $440, respectively)	27,695	33,432	38,088
Depreciation, amortization and accretion	1,525,635	1,285,328	1,003,802
Selling, general, administrative and development expense (including stock-based compensation expense of $87,460, $88,484 and $78,316, respectively)	543,395	497,835	446,542
Other operating expenses	73,220	66,696	68,517
Total operating expenses	3,932,639	3,158,727	2,613,126
OPERATING INCOME	1,853,029	1,612,789	1,486,922
OTHER INCOME (EXPENSE):
Gain (loss) on retirement of long-term obligations	1,168	(79,606)	(3,473)
Other expense (including unrealized foreign currency losses of $23,439, $71,473 and $49,319, respectively)	(47,790)	(134,960)	(62,060)
Total other expense	(727,169)	(782,827)	(621,218)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	1,125,860	829,962	865,704
Income tax provision	(155,501)	(157,955)	(62,505)
NET INCOME	970,359	672,007	803,199
Net (income) loss attributable to noncontrolling interests	(13,934)	13,067	21,711
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION STOCKHOLDERS	956,425	685,074	824,910
Dividends on preferred stock	(107,125)	(90,163)	(23,888)
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION COMMON STOCKHOLDERS	$ 849,300	$ 594,911	$ 801,022
NET INCOME PER COMMON SHARE AMOUNTS:
Basic net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 2.00	$ 1.42	$ 2.02
Diluted net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 1.98	$ 1.41	$ 2.00
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
BASIC (in shares)	425,143	419	395,958
DILUTED (in shares)	429,283	423	400,086
TV Azteca
OTHER INCOME (EXPENSE):
Interest income, TV Azteca, net of interest expense of $1,163, $820 and $1,482, respectively	$ 10,960	$ 11,209	$ 10,547
Interest expense	(1,163)	(820)	(1,482)
Excluding TV Azteca
OTHER INCOME (EXPENSE):
Interest income	25,618	16,479	14,002
Interest expense	$ (717,125)	$ (595,949)	$ (580,234)

CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock-based compensation expense	$ 89,898,000	$ 90,537,000	$ 80,153,000.000
TV Azteca
Interest expense	1,163,000	820,000	1,482,000
Property
Stock-based compensation expense	1,750,000	1,614,000	1,397,000
Services
Stock-based compensation expense	688,000	439,000	440,000
Selling General Administrative And Development Expense
Stock-based compensation expense	87,460,000	88,484,000	78,316,000
Other Expense [Member]
Foreign currency gain (loss)	$ (23,439,000)	$ (71,473,000)	$ (49,319,000)

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 970,359	$ 672,007	$ 803,199
Other comprehensive (loss) income:
Changes in fair value of cash flow hedges, net of tax expense (benefit) of $0, $73 and $(151), respectively	(449)	948	(1,931)
Reclassification of unrealized losses on cash flow hedges to net income, net of tax expense (benefit) of $0, $84 and $(158), respectively	(291)	2,440	3,448
Foreign currency translation adjustments, net of tax expense (benefit) of $3,782, $(24,857) and $(14,247), respectively	(202,819)	(1,078,950)	(526,890)
Other comprehensive loss	(203,559)	(1,075,562)	(525,373)
Comprehensive income (loss)	766,800	(403,555)	277,826
Comprehensive loss attributable to noncontrolling interest	18,218	45,854	64,083
Comprehensive income (loss) attributable to American Tower Corporation stockholders	$ 785,018	$ (357,701)	$ 341,909

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Reclassification of unrealized losses on cash flow hedges to net income, tax	$ 0	$ 84,000	$ (158,000)
Foreign currency translation adjustments, tax	3,782,000	(24,857,000)	(14,247,000)
Net change in fair value of cash flow hedges, tax	$ 0	$ 73,000	$ (151,000)

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive (Loss) Income	Earnings (Distributions) in Excess of Distributions (Earnings)	Noncontrolling Interest	Convertible Preferred Stock Subject to Mandatory Redemption	Convertible Preferred Stock Subject to Mandatory Redemption Accumulated Other Comprehensive (Loss) Income	Convertible Preferred Stock Subject to Mandatory Redemption Noncontrolling Interest	Series A Preferred Stock	Series A Preferred Stock Additional Paid-in Capital	Series A Preferred Stock Convertible Preferred Stock Subject to Mandatory Redemption Preferred Stock	Series B Preferred Stock Convertible Preferred Stock Subject to Mandatory Redemption	Series B Preferred Stock Convertible Preferred Stock Subject to Mandatory Redemption Preferred Stock	Series B Preferred Stock Convertible Preferred Stock Subject to Mandatory Redemption Additional Paid-in Capital	Common Class A	Common Class A Common Stock	Common Class A Additional Paid-in Capital
BALANCE at Dec. 31, 2013	$ 3,590,040	$ 3,976	$ (207,740)	$ 5,130,616	$ (311,220)	$ (1,081,467)	$ 55,875						$ 0		$ 0
BALANCE (shares) at Dec. 31, 2013		(397,674,350)	(2,810,026)										0		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity	119,734	$ 18		119,716
Stock based compensation related activity (shares)		1,753,286
Issuance of common stock—stock purchase plan	5,718	$ 1		5,717
Issuance of common stock - stock purchase plan (shares)		81,115
Issuance of stock											$ 582,659	$ 582,599	$ 60
Issuance of stock (shares)													6,000,000
Changes in fair value of cash flow hedges, net of tax	(1,931)							$ (1,931)	$ (1,966)	$ 35
Reclassification of unrealized losses on cash flow hedges to net income	3,448				3,288		160
Foreign currency translation adjustment, net of tax	(526,890)				(484,323)		(42,567)
Contributions from noncontrolling interest	123,526						123,526
Distributions to noncontrolling interest	(566)						(566)
Purchase of noncontrolling interest	(64,822)			(49,862)			(14,960)
Common stock distributions declared	(556,875)					(556,875)
Preferred stock dividends declared	(23,888)					(23,888)
Net income	803,199					824,910	(21,711)
Net income (loss)	803,199
BALANCE at Dec. 31, 2014	4,053,352	$ 3,995	$ (207,740)	5,788,786	(794,221)	(837,320)	99,792						$ 60		$ 0
BALANCE (shares) at Dec. 31, 2014		(399,508,751)	(2,810,026)										(6,000,000)		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity	117,218	$ 12		117,206
Stock based compensation related activity (shares)		1,253,236
Issuance of common stock—stock purchase plan	6,618	$ 1		6,617
Issuance of common stock - stock purchase plan (shares)		83,292
Issuance of stock														$ 1,337,946	$ 14	$ 1,337,932	$ 2,440,327	$ 259	$ 2,440,068
Issuance of stock (shares)															1,375,000			25,850,000
Changes in fair value of cash flow hedges, net of tax	948				901		47
Reclassification of unrealized losses on cash flow hedges to net income	2,440				2,494		(54)
Foreign currency translation adjustment, net of tax	(1,078,950)				(1,046,170)		(32,780)
Contributions from noncontrolling interest	8,073						8,073
Distributions to noncontrolling interest	(872)						(872)
Common stock distributions declared	(769,517)					(769,517)
Preferred stock dividends declared	(76,772)					(76,772)
Net income	672,007					685,074	(13,067)
Net income (loss)	672,007
BALANCE at Dec. 31, 2015	6,712,818	$ 4,267	$ (207,740)	9,690,609	(1,836,996)	(998,535)	61,139						$ 60		$ 14
BALANCE (shares) at Dec. 31, 2015		(426,695,279)	(2,810,026)										(6,000,000)		(1,375,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity	155,071	$ 19		155,052
Stock based compensation related activity (shares)		1,959,123
Issuance of common stock—stock purchase plan	7,517	$ 1		7,516
Issuance of common stock - stock purchase plan (shares)		86,947
Issuance of stock																	$ 120,785	$ 12	$ 120,773
Issuance of stock (shares)																		1,171,187
Changes in fair value of cash flow hedges, net of tax	(449)				(449)
Reclassification of unrealized losses on cash flow hedges to net income	(291)				(291)
Foreign currency translation adjustments, net of tax, less amounts reclassified to APIC	(179,384)				(170,667)		(8,717)
Foreign currency translation adjustment, net of tax	(202,819)
Contributions from noncontrolling interest	239,484			69,609	9,071		160,804
Distributions to noncontrolling interest	(1,004)						(1,004)
Common stock distributions declared	(927,730)					(927,730)
Preferred stock dividends declared	(107,125)					(107,125)
Net income	970,359					956,425	83
Net income (loss)	956,508
BALANCE at Dec. 31, 2016	$ 6,976,200	$ 4,299	$ (207,740)	$ 10,043,559	$ (1,999,332)	$ (1,076,965)	$ 212,305						$ 60		$ 14
BALANCE (shares) at Dec. 31, 2016		(429,912,536)	(2,810,026)										(6,000,000)		(1,375,000)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 970,359,000	$ 672,007,000	$ 803,199,000
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation, amortization and accretion	1,525,635,000	1,285,328,000	1,003,802,000
Stock-based compensation expense	89,898,000	90,537,000	80,153,000.000
Decrease in restricted cash	5,256,000	16,112,000	7,522,000
Loss on investments, unrealized foreign currency loss and other non-cash expense	127,377,000	146,170,000	64,133,000
Impairments, net loss on sale of long-lived assets, non-cash restructuring and merger related expenses	50,653,000	29,852,000	26,143,000
(Gain) loss on early retirement of long-term obligations	(1,168,000)	79,750,000	3,379,000
Amortization of deferred financing costs, debt discounts and premiums and other non-cash interest	17,702,000	6,932,000	(4,870,000)
Deferred income taxes	26,957,000	7,764,000	1,384,000
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	11,352,000	(56,312,000)	(84,529,000)
Prepaid and other assets	(83,229,000)	(91,113,000)	(1,437,000)
Deferred rent asset	(131,660,000)	(154,959,000)	(122,230,000)
Accounts payable and accrued expenses	(42,862,000)	95,858,000	34,711,000
Accrued interest	34,386,000	(15,641,000)	45,514,000
Unearned revenue	16,557,000	12,945,000	218,393,000
Deferred rent liability	67,764,000	56,076,000	38,378,000
Other non-current liabilities	18,627,000	1,746,000	20,944,000
Cash provided by operating activities	2,703,604,000	2,183,052,000	2,134,589,000
CASH FLOWS FROM INVESTING ACTIVITIES
Payments for purchase of property and equipment and construction activities	(682,505,000)	(728,753,000)	(974,404,000)
Payments for acquisitions, net of cash acquired	(1,416,373,000)	(1,961,056,000)	(1,010,637,000)
Payment for Verizon transaction	(4,748,000)	(5,059,462,000)	0
Proceeds from sale of assets, net of cash	0	0	15,464,000
Proceeds from sales of short-term investments and other non-current assets	13,056,000	1,032,320,000	1,434,831,000
Payments for short-term investments	(750,000)	(1,022,816,000)	(1,395,316,000)
Deposits, restricted cash and other	(16,126,000)	(1,968,000)	(19,486,000)
Cash used for investing activities	(2,107,446,000)	(7,741,735,000)	(1,949,548,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from short-term borrowings, net	0	9,043,000	0
Borrowings under credit facilities	2,446,845,000	6,126,618,000	2,187,000,000
Proceeds from issuance of senior notes, net	3,236,383,000	1,492,298,000	1,415,844,000
Proceeds from term loan	0	500,000,000	0
Proceeds from other borrowings	0	54,549,000	102,070,000
Proceeds from issuance of securities in securitization transaction	0	875,000,000	0
Repayments of notes payable, credit facilities, term loan, senior notes and capital leases	(5,093,747,000)	(6,393,405,000)	(3,903,144,000)
Contributions from noncontrolling interest holders, net	238,480,000	7,201,000	9,098,000
Proceeds from stock options and stock purchase plan	92,473,000	50,716,000	62,276,000
Distributions paid on common stock	(886,116,000)	(710,852,000)	(404,631,000)
Distributions paid on preferred stock	(107,125,000)	(84,647,000)	(16,013,000)
Proceeds from the issuance of common stock, net	0	2,440,327,000	0
Proceeds from the issuance of preferred stock, net	0	1,337,946,000	583,105,000
Purchase of preferred stock assumed in acquisition	0	0	(59,111,000)
Payment for early retirement of long-term obligations	(86,000)	(85,672,000)	(11,593,000)
Deferred financing costs and other financing activities	(26,401,000)	(30,021,000)	(34,670,000)
Purchase of noncontrolling interest	0	0	(64,822,000)
Cash (used for) provided by financing activities	(99,294,000)	5,589,101,000	(134,591,000)
Net effect of changes in foreign currency exchange rates on cash and cash equivalents	(30,389,000)	(23,224,000)	(30,534,000)
NET INCREASE IN CASH AND CASH EQUIVALENTS	466,475,000	7,194,000	19,916,000
CASH AND CASH EQUIVALENTS, BEGINNING OF YEAR	320,686,000	313,492,000	293,576,000
CASH AND CASH EQUIVALENTS, END OF YEAR	$ 787,161,000	$ 320,686,000	$ 313,492,000

Business and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2016

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Business and Summary of Significant Accounting Policies

BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Business—American Tower Corporation (together with its subsidiaries, “ATC” or the “Company”) is one of the largest global real estate investment trusts and a leading independent owner, operator and developer of multitenant communications real estate. The Company’s primary business is the leasing of space on communications sites to wireless service providers, radio and television broadcast companies, wireless data providers, government agencies and municipalities and tenants in a number of other industries, which the Company refers to as its property operations. Additionally, the Company offers tower-related services in the United States, including site acquisition, zoning and permitting and structural analysis, which primarily support its site leasing business, including the addition of new tenants and equipment on its sites, which the Company refers to as its services operations.

The Company’s portfolio primarily consists of towers it owns and towers it operates pursuant to long-term lease arrangements, as well as distributed antenna system (“DAS”) networks, which provide seamless coverage solutions in certain in-building and outdoor wireless environments. In addition to the communications sites in its portfolio, the Company manages rooftop and tower sites for property owners under various contractual arrangements. The Company also holds other telecommunications infrastructure and property interests that it leases to communications service providers and third-party tower operators.

ATC is a holding company that conducts its operations through its directly and indirectly owned subsidiaries and its joint ventures. ATC’s principal domestic operating subsidiaries are American Towers LLC and SpectraSite Communications, LLC. ATC conducts its international operations primarily through its subsidiary, American Tower International, Inc., which in turn conducts operations through its various international holding and operating subsidiaries and joint ventures.

The Company operates as a real estate investment trust for U.S. federal income tax purposes (“REIT”). Accordingly, the Company generally is not subject to U.S. federal income taxes on income generated by its REIT operations, including the income derived from leasing space on its towers, as the Company receives a dividends paid deduction for distributions to stockholders that generally offsets its income and gains. However, the Company remains obligated to pay U.S. federal income taxes on earnings from its domestic taxable REIT subsidiaries (“TRSs”). In addition, the Company’s international assets and operations, regardless of their designation for U.S. tax purposes, continue to be subject to taxation in the foreign jurisdictions where those assets are held or those operations are conducted.

The use of TRSs enables the Company to continue to engage in certain businesses while complying with REIT qualification requirements. The Company may, from time to time, change the election of previously designated TRSs to be included as part of the REIT. As of December 31, 2016, the Company’s REIT qualified businesses included its U.S. tower leasing business, most of its operations in Costa Rica, Germany and Mexico and a majority of its services segment and indoor DAS networks business.

Principles of Consolidation and Basis of Presentation—The accompanying consolidated financial statements include the accounts of the Company and those entities in which it has a controlling interest. Investments in entities that the Company does not control are accounted for using the equity or cost method, depending upon the Company’s ability to exercise significant influence over operating and financial policies. All intercompany accounts and transactions have been eliminated. As of December 31, 2016, the Company has a controlling interest in two joint ventures in Ghana and Uganda with MTN Group Limited (“MTN Group”). The joint ventures are controlled by a holding company of which a wholly owned subsidiary of the Company holds a 51% controlling interest and a wholly owned subsidiary of MTN Group holds a 49% noncontrolling interest. In 2016, the Company established a joint venture (“ATC Europe”) with PGGM in which the Company holds a 51% controlling interest and PGGM holds a 49% noncontrolling interest. This transaction resulted in a reclassification of $9.1 million of foreign currency translation adjustment from Accumulated other comprehensive loss (“AOCI”) to additional paid-in capital. In addition, the Company holds an approximate 75% controlling interest, and South African investors hold an approximate 25% noncontrolling interest, in a subsidiary of the Company in South Africa. The Company holds a 51% controlling interest in ATC Telecom Infrastructure Private Limited (“ATC TIPL”), formerly known as Viom Networks Limited (“Viom”), and the Remaining Shareholders (as defined in note 6) hold a 49% noncontrolling interest.

Significant Accounting Policies and Use of Estimates—The preparation of financial statements in conformity with accounting principles generally accepted in the United States (“GAAP”) requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results may differ from those estimates, and such differences could be material to the accompanying consolidated financial statements. The significant estimates in the accompanying consolidated financial statements include impairment of long-lived assets (including goodwill), asset retirement obligations, revenue recognition, rent expense, stock-based compensation, income taxes and accounting for business combinations and acquisitions of assets. The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued as additional evidence for certain estimates or to identify matters that require additional disclosure.

Accounts Receivable and Deferred Rent Asset—The Company derives the largest portion of its revenues, corresponding accounts receivable and the related deferred rent asset from a relatively small number of tenants in the telecommunications industry, and 56% of its current year revenues are derived from four tenants.

The Company’s deferred rent asset is associated with non-cancellable tenant leases that contain fixed escalation clauses over the terms of the applicable lease in which revenue is recognized on a straight-line basis over the lease term.

The Company mitigates its concentrations of credit risk with respect to notes and trade receivables and the related deferred rent assets by actively monitoring the creditworthiness of its borrowers and tenants. In recognizing tenant revenue, the Company assesses the collectibility of both the amounts billed and the portion recognized in advance of billing on a straight-line basis. This assessment takes tenant credit risk and business and industry conditions into consideration to ultimately determine the collectibility of the amounts billed. To the extent the amounts, based on management’s estimates, may not be collectible, recognition is deferred until such point as collectibility is determined to be reasonably assured. Any amounts that were previously recognized as revenue and subsequently determined to be uncollectible are charged to bad debt expense included in Selling, general, administrative and development expense in the accompanying consolidated statements of operations.

Accounts receivable is reported net of allowances for doubtful accounts related to estimated losses resulting from a tenant’s inability to make required payments and allowances for amounts invoiced whose collectibility is not reasonably assured. These allowances are generally estimated based on payment patterns, days past due and collection history, and incorporate changes in economic conditions that may not be reflected in historical trends, such as tenants in bankruptcy, liquidation or reorganization. Receivables are written-off against the allowances when they are determined to be uncollectible. Such determination includes analysis and consideration of the particular conditions of the account. Changes in the allowances were as follows (in thousands):



	Year Ended December 31,
	2016			2015			2014
Balance as of January 1	$	23,096		$	17,306		$	19,895
Current year increases	49,966			19,878			8,243
Write-offs, recoveries and other (1)	(27,174		)	(14,088		)	(10,832		)
Balance as of December 31,	$	45,888		$	23,096		$	17,306

_______________


(1)	Recoveries includes recognition of revenue resulting from collections of previously reserved amounts.

Functional Currency—The functional currency of each of the Company’s foreign operating subsidiaries is the respective local currency, except for Costa Rica, where the functional currency is the U.S. Dollar. All foreign currency assets and liabilities held by the subsidiaries are translated into U.S. Dollars at the exchange rate in effect at the end of the applicable fiscal reporting period and all foreign currency revenues and expenses are translated at the average monthly exchange rates. Translation adjustments are reflected in equity as a component of AOCI in the consolidated balance sheets and included as a component of Comprehensive income (loss) in the consolidated statements of comprehensive income (loss).

Transactional gains and losses on foreign currency transactions are reflected in Other expense in the consolidated statements of operations. However, the effect from fluctuations in foreign currency exchange rates on intercompany debt that is considered to be permanently reinvested is reflected in AOCI in the consolidated balance sheets and included as a component of comprehensive income (loss). During the year ended December 31, 2016, the Company recorded net foreign currency losses of $153.9 million, of which $105.0 million was recorded in AOCI and $48.9 million was recorded in Other expense.

Cash and Cash Equivalents—Cash and cash equivalents include cash on hand, demand deposits and short-term investments with original maturities of three months or less. The Company maintains its deposits at high quality financial institutions and monitors the credit ratings of those institutions.

Restricted Cash—Restricted cash includes cash pledged as collateral to secure obligations and all cash whose use is otherwise limited by contractual provisions.

Short-Term Investments—Short-term investments consists of highly liquid investments with original maturities in excess of three months.

Property and Equipment—Property and equipment is recorded at cost or, in the case of acquired properties at estimated fair value on the date acquired. Cost for self-constructed towers includes direct materials and labor, capitalized interest and certain indirect costs associated with construction of the tower, such as transportation costs, employee benefits and payroll taxes. The Company begins the capitalization of costs during the pre-construction period, which is the period during which costs are incurred to evaluate the site, and continues to capitalize costs until the tower is substantially completed and ready for occupancy by a tenant. Labor costs capitalized for the years ended December 31, 2016, 2015 and 2014 were $47.7 million, $44.7 million and $48.5 million, respectively. Interest costs capitalized for the years ended December 31, 2016, 2015 and 2014 were $1.5 million, $1.8 million and $2.8 million, respectively.

Expenditures for repairs and maintenance are expensed as incurred. Augmentation and improvements that extend an asset’s useful life or enhance capacity are capitalized.

Depreciation expense is recorded using the straight-line method over the assets’ estimated useful lives. Towers and related assets on leased land are depreciated over the shorter of the estimated useful life of the asset or the term of the corresponding ground lease, taking into consideration lease renewal options and residual value.

Towers or assets acquired through capital leases are recorded net at the present value of future minimum lease payments or the fair value of the leased asset at the inception of the lease. Property and equipment and assets held under capital leases are amortized over the shorter of the applicable lease term or the estimated useful life of the respective assets for periods generally not exceeding twenty years.

The Company reviews its tower portfolio for indicators of impairment on an individual tower basis. Impairments primarily result from a tower not having current tenant leases or from having expenses in excess of revenues. The Company reviews other long-lived assets for impairment whenever events, changes in circumstances or other evidence indicate that the carrying amount of the Company’s assets may not be recoverable. The Company records impairment charges in Other operating expenses in the consolidated statements of operations in the period in which the Company identifies such impairment.

Goodwill and Other Intangible Assets—The Company reviews goodwill for impairment at least annually (as of December 31) or whenever events or circumstances indicate the carrying value of an asset may not be recoverable.

Goodwill is recorded in the applicable segment and assessed for impairment at the reporting unit level. The Company utilizes the two-step impairment test when testing goodwill for impairment and employs a discounted cash flow analysis. The key assumptions utilized in the discounted cash flow analysis include current operating performance, terminal sales growth rate, management’s expectations of future operating results and cash requirements, the current weighted average cost of capital and an expected tax rate. Under the first step of this test, the Company compares the fair value of the reporting unit, as calculated under an income approach using future discounted cash flows, to the carrying amount of the applicable reporting unit. If the carrying amount exceeds the fair value, the Company conducts the second step of this test, in which the implied fair value of the applicable reporting unit’s goodwill is compared to the carrying amount of that goodwill. If the carrying amount of goodwill exceeds its implied fair value, an impairment loss would be recognized for the amount of the excess.

During the years ended December 31, 2016, 2015 and 2014, no potential impairment was identified under the first step of the test, as the fair value of each of the reporting units was in excess of its carrying amount.

Intangible assets that are separable from goodwill and are deemed to have a definite life are amortized over their useful lives, generally ranging from three to twenty years and are evaluated separately for impairment at least annually or whenever events or circumstances indicate that the carrying amount of an asset may not be recoverable.

The Company reviews its network location intangible assets for indicators of impairment on an individual tower basis. Impairments primarily result from a tower not having current tenant leases or from having expenses in excess of revenues. The Company monitors its tenant-related intangible assets (formerly referred to as customer-related intangible assets) on a tenant by tenant basis for indicators of impairment, such as high levels of turnover or attrition, non-renewal of a significant number of contracts or the cancellation or termination of a relationship. The Company assesses recoverability by determining whether the carrying amount of the related assets will be recovered primarily through projected undiscounted future cash flows. If the Company determines that the carrying amount of an asset may not be recoverable, the Company measures any impairment loss based on the projected future discounted cash flows to be provided from the asset or available market information relative to the asset’s fair value, as compared to the asset’s carrying amount. The Company records impairment charges in Other operating expenses in the consolidated statements of operations in the period in which the Company identifies such impairment.

Derivative Financial Instruments—Derivatives are recorded on the consolidated balance sheet at fair value. If a derivative is designated as a cash flow hedge, the effective portions of changes in the fair value of the derivative are recorded in AOCI, as well as a component of comprehensive income (loss), and are recognized in the results of operations when the hedged item affects earnings. Changes in fair value of the ineffective portions of cash flow hedges are recognized in the results of operations. For derivative instruments that are designated and qualify as fair value hedges, changes in value of the derivatives are recorded in Other expense in the consolidated statements of operations in the current period, along with the offsetting gain or loss on the hedged item attributable to the hedged risk. For derivative instruments not designated as hedging instruments, changes in fair value are recognized in the results of operations in the period that the change occurs.

The primary risks managed through the use of derivative instruments is interest rate risk, exposure to changes in the fair value of debt attributable to interest rate risk and currency risk. From time to time, the Company enters into interest rate swap agreements or foreign currency contracts to manage exposure to these risks. Under these agreements, the Company is exposed to counterparty credit risk to the extent that a counterparty fails to meet the terms of a contract. The Company’s exposure is limited to the current value of the contract at the time the counterparty fails to perform. The Company assesses, both at the inception of the hedge and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows or fair values of hedged items. The Company does not hold derivatives for trading purposes.

Fair Value Measurements—The Company determines the fair value of its financial instruments based on the fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value.

Asset Retirement Obligations—When required, the Company recognizes the fair value of obligations to remove its tower assets and remediate the leased land upon which certain of its tower assets are located. Generally, the associated retirement costs are capitalized as part of the carrying amount of the related tower assets and depreciated over their estimated useful lives and the liability is accreted through the obligation’s estimated settlement date. Fair value estimates of asset retirement obligations generally involve discounting of estimated future cash flows. Periodic accretion of such liabilities due to the passage of time is included in Depreciation, amortization and accretion expense in the consolidated statements of operations. Adjustments are also made to the asset retirement obligation liability to reflect changes in the estimates of timing and amount of expected cash flows, with an offsetting adjustment made to the related long-lived tangible asset. The significant assumptions used in estimating the Company’s aggregate asset retirement obligation are: timing of tower removals; cost of tower removals; timing and number of land lease renewals; expected inflation rates; and credit-adjusted, risk-free interest rates that approximate the Company’s incremental borrowing rate.

Income Taxes—As a REIT, the Company generally is not subject to U.S. federal income taxes on income generated by its U.S. REIT operations. However, the Company remains obligated to pay U.S. federal income taxes on certain earnings and continues to be subject to taxation in its foreign jurisdictions. Accordingly, the consolidated financial statements reflect provisions for federal, state, local and foreign income taxes. The Company recognizes deferred tax assets and liabilities for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis, as well as operating loss and tax credit carryforwards. The Company measures deferred tax assets and liabilities using enacted tax rates expected to apply to taxable income in the years in which those temporary differences and carryforwards are expected to be recovered or settled. The effect on deferred tax assets and liabilities as a result of a change in tax rates is recognized in income in the period that includes the enactment date.

The Company periodically reviews its deferred tax assets, and provides valuation allowances if, based on the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. Management assesses the available positive and negative evidence to estimate if sufficient future taxable income will be generated to use the existing deferred tax assets. Valuation allowances would be reversed as a reduction to the provision for income taxes if related deferred tax assets are deemed realizable based on changes in facts and circumstances relevant to the assets’ recoverability.

The Company classifies uncertain tax positions as non-current income tax liabilities unless expected to be paid within one year. The Company reports penalties and tax-related interest expense as a component of the income tax provision and interest income from tax refunds as a component of Other expense in the consolidated statements of operations.

Other Comprehensive Income (Loss)—Other comprehensive income (loss) refers to items excluded from net income that are recorded as an adjustment to equity, net of tax. The Company’s other comprehensive income (loss) primarily consisted of changes in fair value of effective derivative cash flow hedges, foreign currency translation adjustments and reclassification of unrealized losses on effective derivative cash flow hedges. The AOCI balance included foreign currency translation losses of $2.0 billion, $1.8 billion and $0.8 billion for the years ended December 31, 2016, 2015 and 2014, respectively.

Distributions—As a REIT, the Company must annually distribute to its stockholders an amount equal to at least 90% of its REIT taxable income (determined before the deduction for distributed earnings and excluding any net capital gain). Generally, the Company has distributed, and expects to continue to distribute, all or substantially all of its REIT taxable income after taking into consideration its utilization of net operating losses (“NOLs”).

The amount, timing and frequency of future distributions will be at the sole discretion of the Board of Directors and will depend upon various factors, a number of which may be beyond the Company’s control, including the Company’s financial condition and operating cash flows, the amount required to maintain its qualification for taxation as a REIT and reduce any income and excise taxes that the Company otherwise would be required to pay, limitations on distributions in the Company’s existing and future debt and preferred equity instruments, the Company’s ability to utilize NOLs to offset the Company’s distribution requirements, limitations on its ability to fund distributions using cash generated through its TRSs and other factors that the Board of Directors may deem relevant.

Acquisitions—For acquisitions that meet the definition of a business combination, the Company applies the acquisition method of accounting where assets acquired and liabilities assumed are recorded at fair value at the date of each acquisition, and the results of operations are included with those of the Company from the dates of the respective acquisitions. Any excess of the purchase price paid by the Company over the amounts recognized for assets acquired and liabilities assumed is recorded as goodwill. The Company continues to evaluate acquisitions for a period not to exceed one year after the applicable acquisition date of each transaction to determine whether any additional adjustments are needed to the allocation of the purchase price paid for the assets acquired and liabilities assumed. The fair value of the assets acquired and liabilities assumed is typically determined by using either estimates of replacement costs or discounted cash flow valuation methods. When determining the fair value of tangible assets acquired, the Company must estimate the cost to replace the asset with a new asset taking into consideration such factors as age, condition and the economic useful life of the asset. When determining the fair value of intangible assets acquired, the Company must estimate the applicable discount rate and the timing and amount of future tenant cash flows, including rate and terms of renewal and attrition.

Revenue Recognition—The Company’s revenue from leasing arrangements, including fixed escalation clauses present in non-cancellable lease agreements, is reported on a straight-line basis over the term of the respective leases when collectibility is reasonably assured. Escalation clauses tied to the Consumer Price Index (“CPI”) or other inflation-based indices, and other incentives present in lease agreements with the Company’s tenants are excluded from the straight-line calculation. Total property straight-line revenues for the years ended December 31, 2016, 2015 and 2014 were $131.7 million, $155.0 million and $123.7 million, respectively. Amounts billed upfront in connection with the execution of lease agreements are initially deferred and reflected in Unearned revenue in the accompanying consolidated balance sheets and recognized as revenue over the terms of the applicable leases. Amounts billed or received for services prior to being earned are deferred and reflected in Unearned revenue in the accompanying consolidated balance sheets until the criteria for recognition have been met.

Services revenues are derived under contracts or arrangements with customers that provide for billings either on a fixed price basis or a variable price basis, which includes factors such as time and expenses. Revenues are recognized as services are performed, and include estimates for percentage completed. Amounts billed or received for services prior to being earned are deferred and reflected in Unearned revenue in the accompanying consolidated balance sheets until the criteria for recognition have been met.

Rent Expense—Many of the leases underlying the Company’s tower sites have fixed rent escalations, which provide for periodic increases in the amount of ground rent payable by the Company over time. In addition, certain of the Company’s tenant leases require the Company to exercise available renewal options pursuant to the underlying ground lease if the tenant exercises its renewal option. The Company calculates straight-line ground rent expense for these leases based on the fixed non-cancellable term of the underlying ground lease plus all periods, if any, for which failure to renew the lease imposes an economic penalty to the Company such that renewal appears to be reasonably assured.

Total property straight-line ground rent expense for the years ended December 31, 2016, 2015 and 2014 was $67.8 million, $56.1 million and $38.4 million, respectively. The Company records a liability for straight-line ground rent expense in Other non-current liabilities. The Company records prepaid ground rent in Prepaid and other current assets and Notes receivable and other non-current assets in the accompanying consolidated balance sheets according to the anticipated period of benefit.

Selling, General, Administrative and Development Expense—Selling, general and administrative expense consists of overhead expenses related to the Company’s property and services operations and corporate overhead costs not specifically allocable to any of the Company’s individual business operations. Development expense consists of costs related to the Company’s acquisition efforts, costs associated with new business initiatives and project cancellation costs.

Stock-Based Compensation—Stock-based compensation expense is measured at the accounting measurement date based on the fair value of the award and is generally recognized as an expense over the service period, which typically represents the vesting period. The Company provides for accelerated vesting and extended exercise periods of stock options and restricted stock units upon an employee’s death or permanent disability, or upon an employee’s qualified retirement, provided certain eligibility criteria are met. Accordingly, the Company recognizes compensation expense for stock options and time-based restricted stock units (“RSUs”) over the shorter of (i) the four-year vesting period or (ii) the period from the date of grant to the date the employee becomes eligible for such retirement benefits, which may occur upon grant. The expense recognized includes the impact of forfeitures as they occur.

In March 2015 and 2016, the Company granted performance-based restricted stock units (“PSUs”) to its executive officers. Threshold, target and maximum parameters were established for the metrics for each year in the three-year performance period for the March 2015 grants, and for a three-year performance period for the March 2016 grants. The metrics will be used to calculate the number of shares that will be issuable when the awards vest, which may range from zero to 200% of the target amounts. The Company recognizes compensation expense for PSUs over the three-year vesting period, subject to adjustment based on the date the employee becomes eligible for retirement benefits as well as performance relative to grant parameters.

The fair value of stock options is determined using the Black-Scholes option-pricing model and the fair value of restricted stock units is based on the fair value of the Company’s common stock on the date of grant. The Company recognizes all stock-based compensation expense in either Selling, general, administrative and development expense, costs of operations or as part of the costs associated with the construction of the tower assets.

In connection with the vesting of RSUs, the Company withholds from issuance a number of shares of common stock to satisfy certain employee tax withholding obligations arising from such vesting. The shares withheld are considered constructively retired. The Company recognizes the fair value of the shares withheld in Additional paid-in capital on the consolidated balance sheets. As of December 31, 2016, the Company has withheld from issuance an aggregate of 1,219,755 shares, including 218,063 shares related to the vesting of RSUs during the year ended December 31, 2016.

Litigation Costs—The Company periodically becomes involved in various claims and lawsuits that are incidental to its business. The Company regularly monitors the status of pending legal actions to evaluate both the magnitude and likelihood of any potential loss. The Company accrues for these potential losses when it is probable that a liability has been incurred and the amount of loss, or possible range of loss, can be reasonably estimated. Should the ultimate losses on contingencies or litigation vary from estimates, adjustments to those liabilities may be required. The Company also incurs legal costs in connection with these matters and records estimates of these expenses, which are reflected in Selling, general, administrative and development expense in the accompanying consolidated statements of operations.

Earnings Per Common Share—Basic and Diluted—Basic net income per common share represents net income attributable to American Tower Corporation common stockholders divided by the weighted average number of common shares outstanding during the period. Diluted net income per common share represents net income attributable to American Tower Corporation common stockholders divided by the weighted average number of common shares outstanding during the period and any dilutive common share equivalents, including (A) shares issuable upon (i) the vesting of RSUs, (ii) exercise of stock options, and (iii) conversion of the Company’s mandatory convertible preferred stock and (B) shares earned upon the achievement of the parameters established for the PSUs, each to the extent not anti-dilutive. Dilutive common share equivalents also include the dilutive impact of the shares issuable in the Alltel transaction, which is described in notes 15 and 18. The Company uses the treasury stock method to calculate the effect of its outstanding RSUs, PSUs and stock options and uses the if-converted method to calculate the effect of its outstanding mandatory convertible preferred stock.

Retirement Plan—The Company has a 401(k) plan covering substantially all employees who meet certain age and employment requirements. For the years ended December 31, 2016, 2015 and 2014, the Company matched 75% of the first 6% of a participant’s contributions. For the years ended December 31, 2016, 2015 and 2014, the Company contributed $9.1 million, $7.4 million and $6.5 million to the plan, respectively.

Accounting Standards Updates—In May 2014, the Financial Accounting Standards Board (the “FASB”) issued new revenue recognition guidance, which requires an entity to recognize revenue in an amount that reflects the consideration to which the entity expects to be entitled in exchange for the transfer of promised goods or services to customers. The standard will replace most existing revenue recognition guidance and will become effective for the Company on January 1, 2018. Early adoption is permitted for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2016. The standard permits the use of either the retrospective or cumulative effect transition method. Leases are not included in the scope of this standard. The revenue to which the Company must apply this standard is generally limited to services revenue, certain power and fuel charges not covered by lease agreements and other fees charged to customers. As of December 31, 2016, this revenue was approximately 12% of total revenue. Although the Company is still assessing the impact of this standard on its financial statements, it does not expect changes in the timing of revenue recognition to be material to its financial statements.

In January 2016, the FASB issued new guidance on the recognition and measurement of financial assets and financial liabilities. The guidance amends certain aspects of recognition, measurement, presentation and disclosure of financial instruments. This standard is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

In February 2016, the FASB issued new guidance on the accounting for leases. The guidance amends the existing accounting standards for lease accounting, including the requirement that lessees recognize assets and liabilities for leases with terms greater than twelve months in the statement of financial position. Under the new guidance, lessor accounting is largely unchanged. This guidance is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2018. The standard 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. The Company is evaluating the impact this standard will have on its financial statements.

In March 2016, the FASB issued new guidance on the accounting for share-based payment transactions. The guidance amends the accounting for taxes related to stock-based compensation, including how excess tax benefits and a company’s payments for tax withholdings should be classified. This guidance is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2016. The Company early adopted this standard in the second quarter of 2016 and elected to account for forfeitures as they occur, effective January 1, 2016. The adoption of this guidance was not material to the Company’s consolidated financial statements. Additionally, the Company elected to apply the prospective transition method to the amendments related to the presentation of excess tax benefits in the statements of cash flows.

In August 2016, the FASB issued new guidance on certain classifications within the statement of cash flows. The guidance addresses, among other things, how cash receipts and cash payments are presented and classified in the statement of cash flows, including payments for costs related to debt prepayments or extinguishment, as well as payments of contingent consideration after an acquisition. The guidance is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company has early adopted this guidance for the year ended December 31, 2016, and it did not have a material effect on the Company’s financial statements. Prior periods were not retrospectively adjusted.

In November 2016, the FASB issued new guidance on amounts described as restricted cash or restricted cash equivalents within the statement of cash flows. The guidance requires amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period balances on the statement of cash flows. The guidance is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017. The standard is required to be applied using a retrospective transition method to each period presented. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

In January 2017, the FASB issued new guidance that clarifies the definition of a business that an entity uses to determine whether a transaction should be accounted for as an asset acquisition (or disposal) or a business combination. The guidance is expected to cause fewer acquired sets of assets (and liabilities) to be identified as businesses. The guidance is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017. Early adoption is permitted for transactions that meet certain requirements. The Company is evaluating the impact this standard will have on its financial statements.

In January 2017, the FASB issued new guidance that simplifies the accounting for goodwill impairments by eliminating Step 2 from the goodwill impairment test. The guidance requires, among other things, recognition of an impairment loss when the fair value of a reporting unit exceeds its carrying amount. The loss recognized is limited to the total amount of goodwill allocated to that reporting unit. The guidance is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

Property and Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Property and Equipment

PROPERTY AND EQUIPMENT

Property and equipment (including assets held under capital leases) consisted of the following as of December 31, (in thousands):



	Estimated Useful Lives (years) (1)	2016			2015
Towers	Up to 20	$	11,740,479		$	10,726,656
Equipment	2 - 15	1,176,260			1,095,906
Buildings and improvements	3 - 32	621,874			607,661
Land and improvements (2)	Up to 20	1,909,732			1,728,115
Construction-in-progress		203,411			238,960
Total		15,651,756			14,397,298
Less accumulated depreciation		(5,134,498		)	(4,530,874		)
Property and equipment, net		$	10,517,258		$	9,866,424

_______________


(1)	Assets on leased land are depreciated over the shorter of the estimated useful life of the asset or the term of the corresponding ground lease taking into consideration lease renewal options and residual value.


(2)	Estimated useful lives apply to improvements only.

Depreciation expense for the years ended December 31, 2016, 2015 and 2014 was $758.9 million, $661.4 million and $551.8 million, respectively.

As of December 31, 2016, property and equipment included $4,735.3 million and $1,198.0 million of capital lease assets and accumulated depreciation, respectively. As of December 31, 2015, property and equipment included $5,112.4 million and $1,414.6 million of capital lease assets and accumulated depreciation, respectively. The decreases in capital lease assets and accumulated depreciation were primarily due to the Company exercising its option to purchase 1,523 communications towers that were previously subject to capital leases. See note 18 for further discussion of this transaction. As of December 31, 2016 and 2015, capital lease assets were primarily classified as towers and land and improvements.

Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

GOODWILL AND OTHER INTANGIBLE ASSETS

The changes in the carrying value of goodwill for the Company’s business segments were as follows (in thousands):



	Property												Services		Total
	U.S.		Asia				EMEA			Latin America			Services		Total
Balance as of January 1, 2015	$	3,356,096	$	178,521			$	78,647		$	416,922		$	1,988	$	4,032,174
Additions	23,067		610				68,663			122,345			—		214,685
Effect of foreign currency translation	—		(8,412		)		(14,740		)	(131,902		)	—		(155,054		)
Balance as of December 31, 2015	$	3,379,163	$	170,719			$	132,570		$	407,365		$	1,988	$	4,091,805
Additions (1)	—		881,783			(2)	40,386			53,575			—		975,744
Effect of foreign currency translation	—		(23,189		)		(22,445		)	48,765			—		3,131
Balance as of December 31, 2016	$	3,379,163	$	1,029,313			$	150,511		$	509,705		$	1,988	$	5,070,680

_______________


(1)	Additions consist of $975.6 million resulting from 2016 acquisitions and $0.1 million from revisions to prior year acquisitions resulting from measurement period adjustments.


(2)	Assumed in the acquisition of Viom (see note 6).

The Company’s other intangible assets subject to amortization consisted of the following (in thousands):



		As of December 31, 2016							As of December 31, 2015
	Estimated Useful Lives	Gross Carrying Value		Accumulated Amortization			Net Book Value		Gross Carrying Value		Accumulated Amortization			Net Book Value
	(years)	(in thousands)
Acquired network location intangibles (1)	Up to 20	$	4,622,316	$	(1,280,284	)	$	3,342,032	$	3,980,281	$	(1,052,393	)	$	2,927,888
Acquired tenant-related intangibles	15-20	10,130,466		(2,224,119		)	7,906,347		8,640,554		(1,763,853		)	6,876,701
Acquired licenses and other intangibles	3-20	28,140		(4,827		)	23,313		28,293		(5,486		)	22,807
Economic Rights, TV Azteca	70	13,893		(10,974		)	2,919		21,688		(11,208		)	10,480
Total other intangible assets		$	14,794,815	$	(3,520,204	)	$	11,274,611	$	12,670,816	$	(2,832,940	)	$	9,837,876

_______________


(1)	Acquired network location intangibles are amortized over the shorter of the term of the corresponding ground lease taking into consideration lease renewal options and residual value or up to 20 years, as the Company considers these intangibles to be directly related to the tower assets.

The acquired network location intangibles represent the value to the Company of the incremental revenue growth that could potentially be obtained from leasing the excess capacity on acquired communications sites. The acquired tenant-related intangibles typically represent the value to the Company of tenant contracts and relationships in place at the time of an acquisition or similar transaction, including assumptions regarding estimated renewals. This item was previously referred to as customer-related intangibles.

The Company amortizes its acquired network location intangibles and tenant-related intangibles on a straight-line basis over the estimated useful lives. As of December 31, 2016, the remaining weighted average amortization period of the Company’s intangible assets, excluding the TV Azteca Economic Rights detailed in note 5, was 16 years. Amortization of intangible assets for the years ended December 31, 2016, 2015 and 2014 was $699.8 million, $568.3 million and $411.7 million, respectively. Based on current exchange rates, the Company expects to record amortization expense as follows over the next five years (in millions):



Year Ending December 31,
2017	$	710.5
2018	707.8
2019	705.1
2020	686.3
2021	676.8

- Definition

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

Notes Receivable and Other Non-current Assets

12 Months Ended

Dec. 31, 2016

Notes Receivable And Other Long Term Assets [Abstract]

Notes Receivable and Other Non-Current Assets

NOTES RECEIVABLE AND OTHER NON-CURRENT ASSETS

Notes receivable and other non-current assets consisted of the following as of December 31, (in thousands):



	2016		2015
Long-term prepaid ground rent	$	467,781	$	388,790
Notes receivable	83,736		83,658
Other miscellaneous assets	290,006		260,455
Notes receivable and other non-current assets	$	841,523	$	732,903

TV Azteca Note Receivable—In 2000, the Company loaned TV Azteca, S.A. de C.V. (“TV Azteca”), the owner of a major national television network in Mexico, $119.8 million. The loan has an interest rate of 13.11%, payable quarterly, which at the time of issuance was determined to be below market and therefore a corresponding discount was recorded. The term of the loan is 70 years; however, the loan may be prepaid by TV Azteca without penalty during the last 50 years of the agreement. The discount on the loan is being amortized to Interest income, TV Azteca, net of interest expense on the Company’s consolidated statements of operations, using the effective interest method over the 70-year term of the loan.

Since inception, TV Azteca has repaid $28.0 million of principal on the loan. As of December 31, 2016 and 2015, the outstanding balance on the loan was $91.8 million, or $82.9 million, net of discount.

TV Azteca Economic Rights—Simultaneous with the signing of the loan agreement, the Company also entered into a 70-year Economic Rights Agreement with TV Azteca regarding space not used by TV Azteca on approximately 190 of its broadcast towers. In exchange for the issuance of the below market interest rate loan and the annual payment of $1.5 million to TV Azteca (under the Economic Rights Agreement), the Company has the right to market and lease the unused tower space on the broadcast towers (the “Economic Rights”). TV Azteca retains title to these towers and is responsible for their operation and maintenance. The Company is entitled to 100% of the revenues generated from leases with tenants on the unused space and is responsible for any incremental operating expenses associated with those tenants.

The term of the Economic Rights Agreement is 70 years; however, TV Azteca has the right to purchase, at fair market value, the Economic Rights from the Company at any time during the last 50 years of the agreement. Should TV Azteca elect to purchase the Economic Rights, in whole or in part, it would also be obligated to repay a proportional amount of the loan discussed above at the time of such election. The Company’s obligation to pay TV Azteca $1.5 million annually would also be reduced proportionally.

The Company accounted for the annual payment of $1.5 million as a capital lease by initially recording an asset and a corresponding liability of $18.6 million. The capital lease asset also included the original discount on the note. The capital lease asset and original discount on the note aggregated $30.2 million at the time of the transaction and represents the cost to acquire the Economic Rights. The Economic Rights asset was recorded as an intangible asset and is being amortized over the 70-year life of the Economic Rights Agreement.

Acquisitions

12 Months Ended

Dec. 31, 2016

Business Combinations [Abstract]

Acquisitions

ACQUISITIONS

The estimates of the fair value of the assets or rights acquired and liabilities assumed at the date of the applicable acquisition are subject to adjustment during the measurement period (up to one year from the particular acquisition date). The primary areas of the accounting for the acquisitions that are not yet finalized relate to the fair value of certain tangible and intangible assets acquired and liabilities assumed, which may include contingent consideration, residual goodwill and any related tax impact. The fair value of these net assets acquired are based on management’s estimates and assumptions, as well as other information compiled by management, including valuations that utilize customary valuation procedures and techniques. While the Company believes that such preliminary estimates provide a reasonable basis for estimating the fair value of assets acquired and liabilities assumed, it evaluates any necessary information prior to finalization of the fair value. During the measurement period, the Company will adjust assets or liabilities if new information is obtained about facts and circumstances that existed as of the acquisition date that, if known, would have resulted in the revised estimated values of those assets or liabilities as of that date.

Impact of current year acquisitions—The Company typically acquires communications sites from wireless carriers or other tower operators and subsequently integrates those sites into its existing portfolio of communications sites. The financial results of the Company’s acquisitions have been included in the Company’s consolidated statement of operations for the year ended December 31, 2016 from the date of the respective acquisition. The date of acquisition, and by extension the point at which the Company begins to recognize the results of an acquisition, may depend upon, among other things, the receipt of contractual consents, the commencement and extent of leasing arrangements and the timing of the transfer of title or rights to the assets, which may be accomplished in phases. Sites acquired from communications service providers may never have been operated as a business and may have been utilized solely by the seller as a component of its network infrastructure. An acquisition may or may not involve the transfer of business operations or employees.

The estimated aggregate impact of the 2016 acquisitions on the Company’s revenues and gross margin for the year ended December 31, 2016 was approximately $567.9 million and $241.1 million, respectively. The revenues and gross margin amounts also reflect incremental revenues from the addition of new tenants to such sites subsequent to the transaction date. Incremental amounts of segment selling, general, administrative and development expense subsequent to the transaction date have not been reflected.

For those acquisitions accounted for as business combinations, the Company recognizes acquisition and merger related expenses in the period in which they are incurred and services are received. Acquisition and merger related expenses may include finder’s fees, advisory, legal, accounting, valuation and other professional or consulting fees, fair value adjustments to contingent consideration and general administrative costs directly related to the transaction. Integration costs include incremental and nonrecurring costs necessary to convert data, retain employees and otherwise enable the Company to operate new businesses efficiently. The Company records acquisition and merger related expenses, as well as integration costs in Other operating expenses in the consolidated statements of operations.

During the years ended December 31, 2016, 2015 and 2014, the Company recorded the following acquisition and merger related expenses and integration costs (in thousands):



	Year Ended December 31,
	2016		2015		2014

Acquisition and merger related expenses	$	15,875	$	18,799	$	26,969
Integration costs	$	9,901	$	18,097	$	13,057

2016 Transactions

Viom Acquisition—On April 21, 2016, the Company, through its wholly owned subsidiary, ATC Asia Pacific Pte. Ltd. (“ATC Asia”), acquired a 51% controlling ownership interest in Viom, a telecommunications infrastructure company that owns and operates approximately 42,000 wireless communications towers and 200 indoor DAS networks in India, from certain Viom shareholders, including the managing shareholder, SREI Infrastructure Finance Limited, several other minority shareholders and Tata Teleservices Limited, pursuant to its previously announced share purchase agreement (the “Viom Acquisition”). Consideration for the acquisition included 76.4 billion INR in cash ($1.1 billion at the date of the Viom Acquisition), as well as the assumption of approximately 52.3 billion INR ($0.8 billion at the date of the Viom Acquisition) of existing debt, which included 1.7 billion INR ($25.1 million at the date of the Viom Acquisition) of mandatorily redeemable preference shares issued by Viom.

On April 21, 2016, the closing date of the Viom Acquisition, ATC Asia’s shareholders agreement (the “Shareholders Agreement”) with Viom and the following remaining Viom shareholders - Tata Sons Limited, Tata Teleservices Limited, IDFC Private Equity Fund III, Macquarie SBI Investments Pte Limited and SBI Macquarie Infrastructure Trust (collectively, the “Remaining Shareholders”) - became effective. The Shareholders Agreement provides that, among other things, the Remaining Shareholders will have certain governance, anti-dilution and contractual rights. The Remaining Shareholders have put options, and ATC Asia has a call option, subject to the time periods and conditions outlined in the Shareholders Agreement.

Other Acquisitions—During the year ended December 31, 2016, the Company acquired a total of 891 communications sites in the United States, Brazil, Chile, Germany, Mexico, Nigeria and South Africa, and a company holding urban telecommunications assets and fiber in Argentina, for an aggregate purchase price of $304.4 million (including contingent consideration of $8.8 million). Of the total purchase price, $12.1 million is reflected in Accounts payable in the consolidated balance sheet as of December 31, 2016. The purchase prices of certain transactions are subject to post-closing adjustments.

The following table summarizes the preliminary allocation of the purchase prices for fiscal year 2016 acquisitions based upon their estimated fair value at the date of acquisition (in thousands).



	Asia			Other
	Viom			Other
Current assets	$	276,560		$	25,477
Non-current assets	57,645			2,336
Property and equipment	701,988			81,521
Intangible assets (1):
Tenant-related intangible assets	1,369,580			105,557
Network location intangible assets	666,364			83,645
Current liabilities	(195,900		)	(14,782		)
Deferred tax liability	(619,070		)	(43,756		)
Other non-current liabilities	(102,751		)	(29,472		)
Net assets acquired	2,154,416			210,526
Goodwill (2)	881,783			93,856
Fair value of net assets acquired	3,036,199			304,382
Debt assumed	(786,889		)	—
Redeemable noncontrolling interests	(1,100,804		)	—
Purchase Price	$	1,148,506		$	304,382

_______________


(1)	Tenant-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years.


(2)	Primarily results from purchase accounting adjustments, which are at least partially deductible for tax purposes in certain foreign jurisdictions.

2015 Transactions

Verizon Transaction—On March 27, 2015, the Company completed its acquisition of the exclusive right to lease, acquire or otherwise operate and manage 11,449 wireless communications sites from Verizon Communications Inc. (“Verizon”) in the United States (the “Verizon Transaction”) pursuant to the Master Agreement entered into on February 5, 2015 and the related Master Prepaid Lease, Management Agreement, Sale Site Master Lease Agreement and MPL Site Master Lease Agreement.

The Company, through its wholly-owned subsidiary, leased or subleased from certain Verizon subsidiaries 11,286 communications sites, including the interest in the land, the tower and certain related improvements and tower related assets pursuant to the Master Prepaid Lease. Under the Master Prepaid Lease, the Company has the exclusive right to lease and operate the Verizon communications sites for a weighted average term of approximately 28 years and the Company will have the option to purchase the communications sites in various tranches at the end of the respective lease or sublease terms at a fixed amount stated in the sublease for such tranche plus the fair market value of certain alterations made to the related towers. The Company accounted for the payment with respect to the leased sites as a capital lease and the respective lease and non-lease elements related to tower assets and intangible assets, as described below. In addition, the Company, through its wholly-owned subsidiary, acquired 163 communications sites. The Company accounted for these sites as a business combination and the purchase price is reflected below in “Other Acquisitions.”

Upon closing, the Company agreed to lease, sublease or otherwise make available collocation space at each of the communications sites to Verizon for an initial non-cancellable term of ten years, subject to automatic extension for eight additional five-year renewal terms. The initial collocation rent is $1,900 per month for each communications site, with annual increases of 2%.

The total consideration for the Verizon Transaction was $5.066 billion, which includes consideration for the sites under the Master Prepaid Lease as well as cash consideration for the 163 acquired sites. The allocation of the consideration transfered for the 11,286 communication sites under the Master Prepaid Lease was finalized during the year ended December 31, 2015.

Airtel Acquisition—During the year ended December 31, 2015, the Company acquired 4,716 communications sites in Nigeria from certain subsidiaries of Bharti Airtel Limited (“Airtel”) for an aggregate total purchase price of $1.112 billion, including value added tax. During the year ended December 31, 2016 there were no changes to the preliminary allocation of the purchase price and the measurement period expired.

The estimates of the fair value of the assets or rights acquired and liabilities assumed at the date of the applicable acquisition are subject to adjustment during the measurement period (up to one year from the applicable acquisition date). During the year ended December 31, 2016, the Company adopted new guidance on the accounting for measurement-period adjustments related to business combinations. This guidance requires that an acquirer make adjustments to the provisional amounts recognized at the acquisition date with a corresponding adjustment to goodwill in the current period. Additionally, the effects on earnings of all measurement-period adjustments are included in current period earnings.

During the year ended December 31, 2016, post-closing adjustments impacted the following 2015 acquisitions:

TIM Acquisition—On April 29, 2015, the Company acquired 4,176 communications sites from TIM Celular S.A. (“TIM”) for an initial aggregate purchase price of $644.3 million, which was subsequently reduced by $0.8 million during the year ended December 31, 2016. On September 30, 2015, the Company acquired an additional 1,125 communications sites from TIM for an initial aggregate purchase price of $130.9 million. On December 16, 2015, the Company acquired an additional 182 communications sites from TIM for an initial aggregate purchase price of $21.7 million.

Other Acquisitions—During the year ended December 31, 2015, the Company acquired a total of 439 communications sites and related assets in Brazil, India, Mexico and Uganda for an aggregate purchase price of $22.5 million (including $0.3 million for the estimated fair value of contingent consideration), which was satisfied with cash consideration and by the issuance of credits to be applied against trade accounts receivable. The Company also acquired a total of 210 communications sites and equipment, as well as four property interests, in the United States for an aggregate purchase price of $142.4 million (including $1.3 million for the estimated fair value of contingent consideration), which included the 163 communications sites acquired as part of the Verizon Transaction, described above. The initial aggregate purchase price of other acquisitions was subsequently reduced by $0.2 million during the year ended December 31, 2016.

The following table summarizes the preliminary and final allocations of the purchase prices paid and the amounts of assets acquired and liabilities assumed for the fiscal year 2015 acquisitions based upon their estimated fair value at the date of acquisition (in thousands).



	Preliminary Allocation				Final Allocation (1)
	Latin America		Other		Latin America		Other
	TIM		Other		TIM		Other
Current assets	$	—	$	1,113	$	—	$	1,113
Non-current assets	—		995		—		995
Property and equipment	275,630		42,716		274,530		42,716
Intangible assets (2):
Tenant-related intangible assets	361,822		63,001		361,765		62,832
Network location intangible assets	115,562