American Tower (AMT) 10-Q 29 Oct 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 22, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Entity Registrant Name	AMERICAN TOWER CORP /MA/
Entity Central Index Key	1,053,507
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		423,570,172

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 287,404	$ 313,492
Restricted cash	137,926	160,206
Short-term investments	14,485	6,302
Accounts receivable, net	206,154	199,074
Prepaid and other current assets	282,068	264,793	[1]
Deferred income taxes	12,318	14,000
Total current assets	940,355	957,867
PROPERTY AND EQUIPMENT, net	9,806,190	7,590,112
GOODWILL	4,055,171	4,032,174	[2]
OTHER INTANGIBLE ASSETS, net	10,012,397	6,900,162	[3]
DEFERRED INCOME TAXES	200,885	253,186
DEFERRED RENT ASSET	1,123,009	1,030,707
NOTES RECEIVABLE AND OTHER NON-CURRENT ASSETS	788,781	567,724
TOTAL	26,926,788	21,331,932
CURRENT LIABILITIES:
Accounts payable	99,590	90,366
Accrued expenses	743,256	417,836	[4]
Distributions payable	196,833	159,864
Accrued interest	80,682	130,265
Current portion of long-term obligations	45,852	897,624
Unearned revenue	203,295	233,819
Total current liabilities	1,369,508	1,929,774
LONG-TERM OBLIGATIONS	16,981,556	13,711,084
ASSET RETIREMENT OBLIGATIONS	811,620	609,035
OTHER NON-CURRENT LIABILITIES	1,079,902	1,028,687
Total liabilities	$ 20,242,586	$ 17,278,580
COMMITMENTS AND CONTINGENCIES
EQUITY:
Common stock: $.01 par value; 1,000,000,000 shares authorized; 426,307,336 and 399,508,751 shares issued; and 423,497,310 and 396,698,725 shares outstanding, respectively	$ 4,263	$ 3,995
Additional paid-in capital	9,650,129	5,788,786
Distributions in excess of earnings	(995,932)	(837,320)
Accumulated other comprehensive loss	(1,832,903)	(794,221)
Treasury stock (2,810,026 shares at cost)	(207,740)	(207,740)
Total American Tower Corporation equity	6,617,891	3,953,560
Noncontrolling interest	66,311	99,792
Total equity	6,684,202	4,053,352
TOTAL	26,926,788	21,331,932
Series A Preferred Stock
EQUITY:
Preferred stock: $.01 par value: 20,000,000 shares authorized; 5.25%, Series A, 6,000,000 shares issued and outstanding; 5.50%, Series B, 1,375,000 and no shares issued and outstanding, respectively	60	60
Series B Preferred Stock
EQUITY:
Preferred stock: $.01 par value: 20,000,000 shares authorized; 5.25%, Series A, 6,000,000 shares issued and outstanding; 5.50%, Series B, 1,375,000 and no shares issued and outstanding, respectively	$ 14	$ 0
[1]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments
[2]	January 1, 2015 balances have been revised to reflect purchase accounting measurement period adjustments.
[3]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.
[4]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
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	426,307,336	399,508,751
Common stock, shares outstanding	423,497,310	396,698,725
Treasury stock, shares	2,810,026	2,810,026
Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares authorized	20,000,000	20,000,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
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	$ 600,000,000	$ 600,000,000
Preferred stock, dividend rate (percent)	5.25%	5.25%
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, shares issued	1,375,000
Preferred stock, shares outstanding	1,375,000
Preferred stock, aggregate liquidation value	$ 13,750,000
Preferred stock, dividend rate (percent)	5.50%

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
REVENUES:
Rental and management	$ 1,212,849	$ 1,011,119	$ 3,429,264	$ 2,977,000
Network development services	25,061	27,069	62,211	76,734
Total operating revenues	1,237,910	1,038,188	3,491,475	3,053,734
Costs of operations (exclusive of items shown separately below):
Rental and management (including stock-based compensation expense of $396, $344, $1,218 and $1,059, respectively)	356,082	272,355	929,624	786,374
Network development services (including stock-based compensation expense of $99, $101, $336 and $343, respectively)	9,307	11,847	22,863	30,872
Depreciation, amortization and accretion	341,096	249,066	932,972	740,256
Selling, general, administrative and development expense (including stock-based compensation expense of $17,850, $17,824, $70,697 and $60,306, respectively)	114,832	108,909	354,460	317,437
Other operating expenses	15,668	11,204	40,891	37,852
Total operating expenses	836,985	653,381	2,280,810	1,912,791
OPERATING INCOME	400,925	384,807	1,210,665	1,140,943
OTHER INCOME (EXPENSE):
Interest expense	(149,787)	(143,212)	(446,228)	(432,753)
Gain (loss) on retirement of long-term obligations	0	2,969	(78,793)	1,447
Other expense (including unrealized foreign currency losses of $77,864, $36,998, $107,871 and $62,556, respectively)	(66,659)	(34,019)	(123,291)	(54,225)
Total other expense	(208,950)	(167,751)	(628,190)	(469,464)
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	191,975	217,056	582,475	671,479
Income tax provision	(94,235)	(10,426)	(132,063)	(49,877)
NET INCOME	97,740	206,630	450,412	621,602
Net loss attributable to noncontrolling interest	5,259	963	1,960	22,921
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION STOCKHOLDERS	102,999	207,593	452,372	644,523
Dividends on preferred stock	(26,781)	(7,700)	(63,382)	(12,075)
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION COMMON STOCKHOLDERS	$ 76,218	$ 199,893	$ 388,990	$ 632,448
NET INCOME PER COMMON SHARE AMOUNTS:
Basic net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 0.18	$ 0.50	$ 0.93	$ 1.60
Diluted net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 0.18	$ 0.50	$ 0.92	$ 1.58
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
Basic (in shares)	423,375	396,243	417,280	395,758
Diluted (in shares)	427,227	400,397	421,352	399,806
DISTRIBUTIONS DECLARED PER COMMON SHARE	$ 0.46	$ 0.36	$ 1.32	$ 1.02
TV Azteca
OTHER INCOME (EXPENSE):
Interest income, TV Azteca, net of interest expense of $40, $371, $780 and $1,112, respectively	$ 2,993	$ 2,661	$ 8,251	$ 7,918
Interest expense	(40)	(371)	(780)	(1,112)
Excluding TV Azteca
OTHER INCOME (EXPENSE):
Interest income	$ 4,503	$ 3,850	$ 11,871	$ 8,149

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Stock-based compensation expense	$ 18,345	$ 18,269	$ 72,251	$ 61,708
Interest Expense, TV Azteca	149,787	143,212	446,228	432,753
TV Azteca
Interest Expense, TV Azteca	40	371	780	1,112
Rental And Management
Stock-based compensation expense	396	344	1,218	1,059
Network Development Services
Stock-based compensation expense	99	101	336	343
Selling General Administrative And Development Expense
Stock-based compensation expense	17,850	17,824	70,697	60,306
Other Expense
Unrealized foreign currency losses	$ 77,864	$ 36,998	$ 107,871	$ 62,556

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 97,740	$ 206,630	$ 450,412	$ 621,602
Other comprehensive (loss) income:
Changes in fair value of cash flow hedges, net of taxes of ($9), ($7), ($18) and ($31), respectively	710	(519)	365	(856)
Reclassification of unrealized losses on cash flow hedges to net income, net of taxes of $20, $36, $66 and $132, respectively	158	542	2,771	2,085
Foreign currency translation adjustments, net of taxes of $(12,863), $(7,969), $(25,275) and $(8,333), respectively	(600,798)	(254,239)	(1,077,788)	(234,851)
Other comprehensive loss	(599,930)	(254,216)	(1,074,652)	(233,622)
Comprehensive (loss) income	(502,190)	(47,586)	(624,240)	387,980
Comprehensive loss attributable to noncontrolling interest	807	1,760	37,930	63,424
Comprehensive (loss) income attributable to American Tower Corporation stockholders	$ (501,383)	$ (45,826)	$ (586,310)	$ 451,404

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net change in fair value of cash flow hedges, tax	$ (9)	$ (7)	$ (18)	$ (31)
Reclassification of unrealized losses on cash flow hedges to net income, tax	20	36	66	132
Foreign currency translation adjustments, tax	$ 12,863	$ 7,969	$ 25,275	$ 8,333

CONDENSED CONSOLIDATED STATEME8

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS PROVIDED BY OPERATING ACTIVITIES:
Net income	$ 450,412	$ 621,602
Adjustments to reconcile net income to cash provided by operating activities:
Stock-based compensation expense	72,251	61,708
Depreciation, amortization and accretion	932,972	740,256
Loss (gain) on early retirement of long-term obligations	78,793	(1,447)
Other non-cash items reflected in statements of operations	143,412	73,825
Increase in net deferred rent asset	(69,019)	(65,460)
Decrease in restricted cash	19,971	23,560
Increase in assets	(106,535)	(42,931)
Increase in liabilities	21,358	158,493
Cash provided by operating activities	1,543,615	1,569,606
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments for purchase of property and equipment and construction activities	(518,018)	(723,353)
Payments for acquisitions, net of cash acquired	(1,616,205)	(324,936)
Payment for Verizon transaction	(5,058,895)	0
Proceeds from sale of assets, net of cash	0	15,464
Proceeds from sale of short-term investments and other non-current assets	1,002,214	453,396
Payments for short-term investments	(1,011,320)	(460,686)
Deposits, restricted cash and other	(2,053)	(63,295)
Cash used for investing activities	(7,204,277)	(1,103,410)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from short-term borrowings, net	8,282	0
Borrowings under credit facilities	5,727,831	785,000
Proceeds from issuance of senior notes, net	1,492,298	1,415,844
Proceeds from term loan	500,000	0
Proceeds from other long-term borrowings	0	3,033
Proceeds from issuance of securities in securitization transaction	875,000	0
Repayments of notes payable, credit facilities, senior notes and capital leases	(6,092,710)	(2,928,434)
Contributions from noncontrolling interest holders, net	4,449	5,446
Proceeds from stock options and stock purchase plan	29,324	47,938
Proceeds from the issuance of common stock, net	2,440,327	0
Proceeds from the issuance of preferred stock, net	1,337,946	583,105
Payment for early retirement of long-term obligations	(86,107)	(6,767)
Deferred financing costs and other financing activities	(30,314)	(32,129)
Purchase of noncontrolling interest	0	(64,822)
Distributions paid on common stock	(516,012)	(261,913)
Distributions paid on preferred stock	(57,866)	(8,138)
Cash provided by (used for) financing activities	5,632,448	(461,837)
Net effect of changes in foreign currency exchange rates on cash and cash equivalents	2,126	(2,322)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(26,088)	2,037
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	313,492	293,576
CASH AND CASH EQUIVALENTS, END OF PERIOD	287,404	295,613
CASH PAID FOR INCOME TAXES (NET OF REFUNDS OF $5,206 AND $6,642, RESPECTIVELY)	130,231	52,379
CASH PAID FOR INTEREST	472,079	438,404
NON-CASH INVESTING AND FINANCING ACTIVITIES:
(DECREASE) INCREASE IN ACCOUNTS PAYABLE AND ACCRUED EXPENSES FOR PURCHASES OF PROPERTY AND EQUIPMENT AND CONSTRUCTION ACTIVITIES	(6,703)	16,070
PURCHASES OF PROPERTY AND EQUIPMENT UNDER CAPITAL LEASES	19,870	24,002
SETTLEMENT OF ACCOUNTS RECEIVABLE RELATED TO ACQUISITIONS	735	31,849
CONVERSION OF THIRD-PARTY DEBT TO EQUITY	$ 0	$ 7,750

CONDENSED CONSOLIDATED STATEME9

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Statement of Cash Flows [Abstract]
Proceeds from income tax refunds	$ 5,206	$ 6,642

CONDENSED CONSOLIDATED STATEM10

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Series A Preferred Stock	Series B Preferred Stock	Preferred StockSeries A Preferred Stock	Preferred StockSeries B Preferred Stock	Common Stock	Treasury Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Distributions in Excess of Earnings	Noncontrolling Interest
BEGINNING BALANCE (shares) at Dec. 31, 2013						397,674,350	(2,810,026)
BEGINNING BALANCE at Dec. 31, 2013	$ 3,590,040					$ 3,976	$ (207,740)	$ 5,130,616	$ (311,220)	$ (1,081,467)	$ 55,875
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity (shares)						1,489,577
Stock-based compensation related activity	90,997					$ 15		90,982
Issuance of common stock - stock purchase plan (in shares)						43,589
Issuance of common stock- stock purchase plan	2,899					$ 1		2,898
Issuance of preferred stock, (shares)				6,000,000
Issuance of preferred stock	582,659			$ 60				582,599
Changes in fair value of cash flow hedges, net of tax	(856)								(969)		113
Reclassification of unrealized losses on cash flow hedges to net income, net of tax	2,085								1,941		144
Foreign currency translation adjustment, net of tax	(234,851)								(194,091)		(40,760)
Contributions from noncontrolling interest	13,626										13,626
Distributions to noncontrolling interest	(430)										(430)
Purchase of noncontrolling interest	(64,822)							(49,862)			(14,960)
Common stock distributions declared	(405,560)									(405,560)
Preferred stock dividends declared	(12,075)									(12,075)
Net income (loss)	621,602									644,523	(22,921)
ENDING BALANCE (shares) at Sep. 30, 2014						399,207,516	(2,810,026)
ENDING BALANCE at Sep. 30, 2014	$ 4,185,314			$ 60		$ 3,992	$ (207,740)	5,757,233	(504,339)	(854,579)	(9,313)
Preferred Stock Ending Balance (shares) at Sep. 30, 2014				6,000,000
BEGINNING BALANCE (shares) at Dec. 31, 2014	396,698,725					399,508,751	(2,810,026)
BEGINNING BALANCE at Dec. 31, 2014	$ 4,053,352			$ 60		$ 3,995	$ (207,740)	5,788,786	(794,221)	(837,320)	99,792
Preferred Stock Beginning Balance (shares) at Dec. 31, 2014		6,000,000		6,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity (shares)						904,645
Stock-based compensation related activity	79,887					$ 9		79,878
Issuance of common stock - stock purchase plan (in shares)						43,940
Issuance of common stock- stock purchase plan	3,465					$ 0		3,465
Issuance of common stock, (shares)						25,850,000
Issuance of common stock	2,440,327					$ 259		2,440,068
Issuance of preferred stock, (shares)					1,375,000
Issuance of preferred stock	1,337,946				$ 14			1,337,932
Changes in fair value of cash flow hedges, net of tax	365								377		(12)
Reclassification of unrealized losses on cash flow hedges to net income, net of tax	2,771								2,728		43
Foreign currency translation adjustment, net of tax	(1,077,788)								(1,041,787)		(36,001)
Contributions from noncontrolling interest	5,105										5,105
Distributions to noncontrolling interest	(656)										(656)
Common stock distributions declared	(560,993)									(560,993)
Preferred stock dividends declared	(49,991)									(49,991)
Net income (loss)	$ 450,412									452,372	(1,960)
ENDING BALANCE (shares) at Sep. 30, 2015	423,497,310					426,307,336	(2,810,026)
ENDING BALANCE at Sep. 30, 2015	$ 6,684,202			$ 60	$ 14	$ 4,263	$ (207,740)	$ 9,650,129	$ (1,832,903)	$ (995,932)	$ 66,311
Preferred Stock Ending Balance (shares) at Sep. 30, 2015		6,000,000	1,375,000	6,000,000	1,375,000

Description of Business, Basis

Description of Business, Basis of Presentation and Accounting Policies	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Basis of Presentation and Accounting Policies	Description of Business, Basis of Presentation and Accounting Policies Business —American Tower Corporation is, through its various subsidiaries (collectively, “ATC” or the “Company”), 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 multitenant 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. The Company also manages rooftop and tower sites for property owners, operates in-building and outdoor distributed antenna system (“DAS”) networks, holds property interests under third-party communications sites and provides network development services that primarily support its rental and management operations. 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”) and, therefore, is generally not subject to U.S. federal income taxes in that it receives a dividends paid deduction for distributions to stockholders that generally offsets the Company’s income and gains, including the income derived from leasing space on its towers. However, the Company remains obligated to pay income taxes on earnings from its taxable REIT subsidiaries (“TRSs”). In addition, the Company’s international assets and operations, including those designated as direct or indirect qualified REIT subsidiaries or other disregarded entities of a REIT (collectively, “QRSs”), continue to be subject to taxation in the foreign jurisdictions where those assets are held or those operations are conducted. As of September 30, 2015 , the Company’s QRSs included its domestic tower leasing business, most of its operations in Costa Rica, Germany and Mexico and a majority of its network development services segment and indoor DAS networks business. On March 27, 2015, the Company significantly expanded its domestic portfolio by obtaining the exclusive right to lease, acquire or otherwise operate and manage 11,448 wireless communications sites from Verizon Communications Inc. (“Verizon”) in the United States (the “Verizon Transaction”). On July 1, 2015, the Company expanded into a new country by acquiring 4,699 communications sites in Nigeria. The accompanying condensed consolidated financial statements have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission. The financial information included herein is unaudited; however, the Company believes that all adjustments (consisting primarily of normal recurring adjustments) considered necessary for a fair presentation of its financial position and results of operations for such periods have been included. These condensed consolidated financial statements and related notes should be read in conjunction with the Company’s Annual Report on Form 10-K for the year ended December 31, 2014 (the “2014 Form 10-K”). Principles of Consolidation and Basis of Presentation —The accompanying condensed 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. 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 condensed consolidated financial statements and accompanying notes. Actual results may differ from those estimates, and such differences could be material to the accompanying condensed consolidated financial statements. The significant estimates in the accompanying condensed 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. 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 in GAAP and will become effective for the Company on January 1, 2018. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2016. The standard permits the use of either the retrospective or cumulative effect transition method and leases are not included in the scope of this standard. The Company is evaluating the impact this standard will have on its financial statements. In June 2014, the FASB issued stock-based compensation guidance, which requires a performance target that could be achieved after the requisite service period be treated as a performance condition that affects vesting, rather than a condition that affects the grant-date fair value. The Company early adopted this guidance on a prospective basis during the nine months ended September 30, 2015 , and it did not have a material effect on the Company’s financial statements. In April 2015, the FASB issued new guidance on the presentation of debt issuance costs. The guidance requires debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability, consistent with debt discounts and premiums. In August 2015, the FASB clarified that debt issuance costs associated with line of credit arrangements may continue to be presented as an asset, regardless of whether there are any outstanding borrowings on the line of credit arrangement. The update requires retrospective application and the update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2015, with early adoption permitted. The Company does not expect the adoption of this guidance to have a material effect on its financial statements. In September 2015, the FASB issued new guidance on the accounting for measurement-period adjustments. The guidance requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined rather than retrospectively. The effect on earnings as a result of the change to the provisional amounts is calculated as if the accounting had been completed as of the acquisition date. The update requires prospective application and the update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2015, with early adoption permitted. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

Prepaid and Other Current Asset

Prepaid and Other Current Assets	9 Months Ended
	Sep. 30, 2015
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid and Other Current Assets	Prepaid and Other Current Assets Prepaid and other current assets consisted of the following as of (in thousands): September 30, 2015 December 31, 2014 (1) Prepaid operating ground leases $ 112,965 $ 88,053 Prepaid assets 41,294 23,848 Prepaid income tax 34,332 34,512 Unbilled receivables 31,878 25,352 Value added tax and other consumption tax receivables 20,727 23,228 Other miscellaneous current assets 40,872 69,800 Balance $ 282,068 $ 264,793 (1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2015
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): Rental and Management Network Development Services Total Domestic International Balance as of January 1, 2015 (1) $ 3,356,096 $ 674,090 $ 1,988 $ 4,032,174 Additions 19,677 145,431 — 165,108 Effect of foreign currency translation — (142,111 ) — (142,111 ) Balance as of September 30, 2015 $ 3,375,773 $ 677,410 $ 1,988 $ 4,055,171 (1) January 1, 2015 balances have been revised to reflect purchase accounting measurement period adjustments. The Company’s other intangible assets subject to amortization consisted of the following as of (in thousands): September 30, 2015 December 31, 2014 (1) Estimated Useful Lives Gross Carrying Value Accumulated Amortization Net Book Value Gross Carrying Value Accumulated Amortization Net Book Value (years) Acquired network location intangibles (2) Up to 20 $ 3,952,072 $ (1,000,656 ) $ 2,951,416 $ 2,513,788 $ (901,903 ) $ 1,611,885 Acquired customer-related intangibles 15-20 8,606,612 (1,666,473 ) 6,940,139 6,594,469 (1,429,572 ) 5,164,897 Acquired licenses and other intangibles 3-20 28,267 (5,333 ) 22,934 38,443 (3,514 ) 34,929 Economic Rights, TV Azteca 70 22,021 (11,331 ) 10,690 25,522 (12,960 ) 12,562 Total $ 12,608,972 $ (2,683,793 ) $ 9,925,179 $ 9,172,222 $ (2,347,949 ) $ 6,824,273 Deferred financing costs, net (3) N/A 87,218 75,889 Other intangible assets, net $ 10,012,397 $ 6,900,162 (1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments. (2) 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. (3) Deferred financing costs are amortized over the term of the respective debt instruments to which they relate using the effective interest method. This amortization is included in Interest expense rather than in Depreciation, amortization and accretion expense. 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 customer-related intangibles typically represent the value to the Company of customer contracts and relationships in place at the time of an acquisition, including assumptions regarding estimated renewals. The Company amortizes its acquired network location intangibles and customer-related intangibles on a straight-line basis over their estimated useful lives. As of September 30, 2015 , the remaining weighted average amortization period of the Company’s intangible assets, excluding deferred financing costs and the TV Azteca Economic Rights detailed in note 5 to the Company’s consolidated financial statements included in the 2014 Form 10-K, was approximately 16 years . Amortization of intangible assets for the three and nine months ended September 30, 2015 was approximately $154.4 million and $412.5 million , respectively, and amortization of intangible assets for the three and nine months ended September 30, 2014 was approximately $103.3 million and $307.5 million , respectively. Amortization expense excludes amortization of deferred financing costs, which is included in Interest expense on the condensed consolidated statements of operations. Based on current exchange rates, the Company expects to record amortization expense (excluding amortization of deferred financing costs) as follows over the remaining current year and the five subsequent years (in millions): Fiscal Year 2015 (remaining year) $ 149.5 2016 594.7 2017 593.2 2018 592.0 2019 589.7 2020 572.0

Accrued Expenses

Accrued Expenses	9 Months Ended
	Sep. 30, 2015
Accrued Liabilities, Current [Abstract]
Accrued Expenses	Accrued Expenses Accrued expenses consisted of the following as of (in thousands): September 30, 2015 December 31, 2014 (1) Acquisition liability (2) $ 300,000 $ — Accrued property and real estate taxes 74,352 61,206 Accrued rent 54,686 34,074 Payroll and related withholdings 50,852 57,110 Accrued construction costs 22,030 46,024 Other accrued expenses 241,336 219,422 Balance $ 743,256 $ 417,836 (1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments. (2) Represents the remaining liability related to the Airtel acquisition on July 1, 2015 (see note 14).

Long-Term Obligations

Long-Term Obligations	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Long-Term Obligations	Long-Term Obligations Refinancing of GTP Acquisition Partners Securitization —On May 29, 2015, GTP Acquisition Partners I, LLC (“GTP Acquisition Partners”), one of the Company’s wholly owned subsidiaries, repaid all amounts outstanding under the Secured Tower Revenue Notes, Global Tower Series 2011-1, Class C, Secured Tower Revenue Notes, Global Tower Series 2011-2, Class C and Class F and Secured Tower Revenue Notes, Global Tower Series 2013-1, Class C and Class F (collectively, the “Existing GTP AP Notes”), plus prepayment consideration and other costs and expenses related thereto, with cash on hand and proceeds from a private issuance (the “2015 Securitization”) of $350.0 million of American Tower Secured Revenue Notes, Series 2015-1, Class A (the “Series 2015-1 Notes”) and $525.0 million of American Tower Secured Revenue Notes, Series 2015-2, Class A (the “Series 2015-2 Notes,” and together with the Series 2015-1 Notes, the “2015 Notes”). During the nine months ended September 30, 2015, the Company recorded a loss on retirement of long-term obligations of $0.8 million , consisting of prepayment consideration, primarily offset by the write-off of the unamortized premium recorded in connection with the assumption of the Existing GTP AP Notes. The 2015 Notes were issued by GTP Acquisition Partners pursuant to a Third Amended and Restated Indenture and related series supplements, each dated as of May 29, 2015 (collectively, the “Indenture”), between GTP Acquisition Partners and its subsidiaries (the “GTP Entities”) and The Bank of New York Mellon, as trustee. The Series 2015-1 Notes have an interest rate of 2.350% , an anticipated repayment date of June 15, 2020 and a final repayment date of June 15, 2045. The Series 2015-2 Notes have an interest rate of 3.482% , an anticipated repayment date of June 16, 2025 and a final repayment date of June 15, 2050. Amounts due under the 2015 Notes will be paid solely from the cash flows generated from the operation of the 3,621 communications sites (the “Secured Sites”) owned by the GTP Entities. GTP Acquisition Partners is required to make monthly payments of interest on the 2015 Notes, commencing in July 2015. Subject to certain limited exceptions (described below), no payments of principal will be required to be made prior to June 15, 2020, which is the anticipated repayment date for the Series 2015-1 Notes. On a monthly basis, after payment of all required amounts under the applicable agreement, the excess cash flows generated from the operation of the Secured Sites are released to GTP Acquisition Partners, which can then be distributed to, and used by, the Company. However, if the debt service coverage ratio (“DSCR”), generally calculated as the ratio of the net cash flow (as defined in the Indenture) to the amount of interest, servicing fees and trustee fees required to be paid over the succeeding 12 months on the principal amount of the 2015 Notes that will be outstanding on the next payment date were equal to or below 1.30 x (the “Cash Trap DSCR”) for such quarter, then all cash flow in excess of amounts required to make debt service payments, to fund required reserves, to pay management fees and budgeted operating expenses and to make other payments required under the transaction documents, referred to as excess cash flow, will be deposited into a reserve account instead of being released to GTP Acquisition Partners. The funds in the reserve account will not be released to GTP Acquisition Partners unless the DSCR exceeds the Cash Trap DSCR for two consecutive calendar quarters. Additionally, an “amortization period” commences if, as of the end of any calendar quarter, the DSCR falls below 1.15 x (the “Minimum DSCR”) and will continue to exist until the DSCR exceeds the Minimum DSCR for two consecutive calendar quarters. During an amortization period, all excess cash flow and any amounts then in the reserve account because the Cash Trap DSCR was not met would be applied to payment of the principal on the 2015 Notes. The 2015 Notes may be prepaid in whole or in part at any time, provided such payment is accompanied by the applicable prepayment consideration. If prepayment occurs within 12 months of the anticipated repayment date with respect to the Series 2015-1 Notes, or 18 months of the anticipated repayment date with respect to the Series 2015-2 Notes, no prepayment consideration is due. If the Series 2015-1 Notes or the Series 2015-2 Notes have not been repaid in full on the applicable anticipated repayment date, additional interest will accrue on the unpaid principal balance of the applicable series of the 2015 Notes, and such series will begin to amortize on a monthly basis from excess cash flow. The 2015 Notes are secured by (i) mortgages, deeds of trust and deeds to secure debt on substantially all of the Secured Sites and their operating cash flows, (ii) a security interest in substantially all of the personal property and fixtures of the GTP Entities, including GTP Acquisition Partners’ equity interests in its subsidiaries and (iii) the rights of the GTP Entities under a management agreement. American Tower Holding Sub II, LLC, whose only material assets are its equity interests in GTP Acquisition Partners, has guaranteed repayment of the 2015 Notes and pledged its equity interests in GTP Acquisition Partners as security for such payment obligations. The Indenture includes covenants customary for notes issued in rated securitizations. Among other things, the GTP Entities are prohibited from incurring other indebtedness for borrowed money or further encumbering their assets. The organizational documents of the GTP Entities contain provisions consistent with rating agency securitization criteria for special purpose entities, including the requirement that they maintain independent directors. The Indenture also contains certain covenants that require GTP Acquisition Partners to provide the trustee with regular financial reports and operating budgets, promptly notify the trustee of events of default and material breaches under the Indenture and other agreements related to the Secured Sites and allow the trustee reasonable access to the Secured Sites, including the right to conduct site investigations. Further, under the Indenture, GTP Acquisition Partners is required to maintain reserve accounts, including for amounts received or due from tenants related to future periods, property taxes, insurance, ground rents, certain expenses and debt service. The $16.0 million held in the reserve accounts as of September 30, 2015 is classified as restricted cash on the Company’s accompanying condensed consolidated balance sheet. Securitized Debt —The Company has several securitizations in place. Cash flows generated by the sites that secure the securitized debt are only available for payment of such debt and are not available to pay the Company’s other obligations or the claims of its creditors. However, subject to certain restrictions, the Company holds the right to the excess cash flows not needed to pay the securitized debt and other obligations arising out of the securitizations. The securitized debt is the obligation of the issuers thereof or borrowers thereunder, as applicable, and their subsidiaries, and not of the Company or its other subsidiaries. Mexican Loan —In May 2015, upon maturity of its 5.2 billion Mexican Peso (“MXN”) denominated unsecured bridge loan, the Company repaid the remaining outstanding principal balance of 3.9 billion MXN (approximately $251.2 million on the date of repayment) with cash on hand and borrowings under its multi-currency senior unsecured revolving credit facility entered into in June 2013, as amended (the “2013 Credit Facility”). BR Towers Credit Facility— On March 30, 2015, the Company repaid all amounts outstanding and terminated the Brazilian Reais (“BRL”) denominated credit facility with Banco Nacional de Desenvolvimento Econômico e Social (“BNDES”), which allowed a subsidiary of BR Towers S.A. (“BR Towers”) to borrow up to 48.1 million BRL through an intermediary bank, and which the Company assumed in connection with the acquisition of BR Towers in November 2014. Brazil Credit Facility— In December 2014, one of the Company’s Brazilian subsidiaries entered into a 271.0 million BRL-denominated credit facility with BNDES, which matures on January 15, 2022 (the “Brazil Credit Facility”). The Brazilian subsidiary borrowed 40.0 million BRL (approximately $13.3 million on the date of borrowing) on May 18, 2015 and an additional 9.1 million BRL (approximately $2.5 million on the date of borrowing) on August 25, 2015. The Brazilian subsidiary maintains the ability to draw on the Brazil Credit Facility until December 30, 2016. The Brazil Credit Facility bears interest at a margin over the long-term interest rate, as defined by BNDES (“TJLP”), and the Special Clearance and Escrow System (“SELIC”) as follows (BRL in millions): Maximum Borrowing Amount Contractual Interest Rate Tranche A BRL 34.8 TJLP + 4.25% Tranche B BRL 34.8 SELIC + 4.25% Tranche C BRL 200.0 6.00 % Tranche D BRL 1.4 TJLP As of September 30, 2015, the Company had 49.8 million BRL (approximately $12.5 million ) outstanding under the Brazil Credit Facility, including capitalized interest, and the weighted average interest rate on the borrowings was 11.2% . Indian Working Capital Facility —In April 2013, one of the Company’s Indian subsidiaries (“ATC India”) entered into a working capital facility agreement (the “Indian Working Capital Facility”), which allows ATC India to borrow an amount not to exceed the Indian Rupee (“INR”) equivalent of $10.0 million through two separate facilities. Advances under one facility (“Facility A”) are payable on the earlier of demand or six months following the borrowing date and advances under the other facility (“Facility B”) are payable on the earlier of demand or 30 days following the borrowing date, with the option to extend for additional 30-day periods. The interest rate is determined at the time of advance by the bank. As of September 30, 2015, the Company had no amounts outstanding under Facility A and 530.0 million INR (approximately $8.1 million ) outstanding under Facility B, with an interest rate of 10.0% . ATC India maintains the ability to draw down and repay amounts under the Indian Working Capital Facility in the ordinary course. 2014 Credit Facility —During the nine months ended September 30, 2015 , the Company increased the maximum Revolving Loan Commitment (as defined in the loan agreement) under its senior unsecured revolving credit facility entered into in January 2012, as amended and restated in September 2014 (the “2014 Credit Facility”) to $2.5 billion . Effective February 20, 2015, the Company received incremental commitments of $500.0 million , and as a result, has the ability to borrow up to $2.0 billion . During the nine months ended September 30, 2015, the Company borrowed an aggregate of $2.1 billion and repaid an aggregate of $1.3 billion of revolving indebtedness under the 2014 Credit Facility. The Company primarily used the borrowings to fund a portion of the Verizon Transaction. 2013 Credit Facility— During the nine months ended September 30, 2015 , the Company increased the maximum Revolving Loan Commitment (as defined in the loan agreement) under the 2013 Credit Facility to $3.5 billion . Effective February 20, 2015, the Company received incremental commitments of $750.0 million , and as a result, has the ability to borrow up to $2.75 billion . During the nine months ended September 30, 2015 , the Company borrowed an aggregate of $3.6 billion and repaid an aggregate of $2.5 billion of revolving indebtedness under the 2013 Credit Facility. The Company primarily used the borrowings to (i) fund a portion of the Verizon Transaction, (ii) fund the Company’s acquisition in Nigeria, (iii) fund the TIM Celular S.A. (“TIM”) acquisition and (iv) repay other indebtedness. The 2014 Credit Facility and the 2013 Credit Facility do not require amortization of principal and may be paid prior to maturity in whole or in part at the Company’s option without penalty or premium. The Company maintains the ability to draw down and repay amounts under each of the credit facilities in the ordinary course. Term Loan— In October 2013, the Company entered into an unsecured term loan (the “Term Loan”). During the nine months ended September 30, 2015, the Company increased the maximum Incremental Term Loan Commitments (as defined in the agreement), giving the Company the ability to increase commitments to an aggregate of $2.5 billion . Effective February 20, 2015, the Company borrowed an additional $500.0 million under the Term Loan. The key terms under the 2014 Credit Facility, the 2013 Credit Facility and the Term Loan as of September 30, 2015 are as follows ($ in millions): Outstanding Balance Undrawn LOC Maturity Date(1) Current margin over LIBOR (3) Current commitment fee (4) 2014 Credit Facility $ 1,980 $ 7.5 January 31, 2020 (2) 1.250 % 0.150 % 2013 Credit Facility $ 1,080 $ 3.2 June 28, 2018 (2) 1.250 % 0.150 % Term Loan $ 2,000 N/A January 3, 2019 1.250 % N/A (1) In October 2015, the Company entered into amendment agreements, which, among other things, extended the maturity dates for the 2014 Credit Facility, the 2013 Credit Facility and the Term Loan to January 29, 2021, June 28, 2019 and January 29, 2021, respectively (see note 16). (2) Subject to two optional renewal periods. (3) LIBOR means the London Interbank Offered Rate. (4) Fee on undrawn portion of the credit facility. Amendments to Bank Facilities —In February 2015, the Company entered into amendment agreements with respect to the 2014 Credit Facility, the 2013 Credit Facility and the Term Loan. After giving effect to these amendments, the Company’s permitted ratio of Total Debt to Adjusted EBITDA (as defined in the loan agreements for each of the facilities) is (i) 7.00 to 1.00 for the quarters ended September 30, 2015 and December 31, 2015 and (ii) 6.00 to 1.00 thereafter. Effective October 28, 2015, the Company entered into additional amendment agreements to the 2013 Credit Facility, the 2014 Credit Facility and the Term Loan (see note 16). Redemption of Senior Notes —On February 11, 2015, the Company redeemed all of the outstanding 4.625% senior notes due 2015 (the “ 4.625% Notes”), in accordance with the redemption provisions in the indenture, at a price equal to 100.5898% of the principal amount, plus accrued interest up to, but excluding, February 11, 2015, for an aggregate redemption price of approximately $613.6 million , including approximately $10.0 million in accrued and unpaid interest. On April 29, 2015, the Company redeemed all of the outstanding 7.000% senior notes due 2017 (the “ 7.000% Notes”), in accordance with the redemption provisions in the indenture, at a price equal to 114.0629% of the principal amount, plus accrued and unpaid interest up to, but excluding, April 29, 2015, for an aggregate redemption price of approximately $571.7 million , including approximately $1.4 million in accrued and unpaid interest. During the nine months ended September 30, 2015, the Company recorded a loss on retirement of long-term obligations of $74.3 million related to the redemption of the 7.000% Notes, and $3.7 million related to the redemption of the 4.625% Notes, each of which included prepayment consideration and the remaining portion of the unamortized discount and deferred financing costs, and with respect to the 7.000% Notes, the write-off of the unamortized portion of the settlement cost of a treasury rate lock. These redemptions were funded with borrowings under the Company’s existing credit facilities and cash on hand. Upon completion of these redemptions, none of the 4.625% Notes or the 7.000% Notes remained outstanding. 2.800% Senior Notes and 4.000% Senior Notes Offering —On May 7, 2015, the Company completed a registered public offering of $750.0 million aggregate principal amount of 2.800% senior unsecured notes due 2020 (the “ 2.800% Notes”) and $750.0 million aggregate principal amount of 4.000% senior unsecured notes due 2025 (the “ 4.000% Notes”). The net proceeds from this offering were approximately $1,480.1 million , after deducting commissions and estimated expenses. The Company used the proceeds to repay existing indebtedness under the 2013 Credit Facility. The 2.800% Notes will mature on June 1, 2020 and bear interest at a rate of 2.800% per annum. The 4.000% Notes will mature on June 1, 2025 and bear interest at a rate of 4.000% per annum. Accrued and unpaid interest on the notes will be payable in U.S. Dollars semi-annually in arrears on June 1 and December 1 of each year, beginning on December 1, 2015. Interest on the notes will accrue from May 7, 2015 and will be computed on the basis of a 360-day year comprised of twelve 30-day months. The Company may redeem the notes at any time, in whole or in part, at the applicable redemption price. If the Company redeems the 2.800% Notes prior to May 1, 2020 or the 4.000% Notes prior to March 1, 2025, it will pay a redemption price equal to 100% of the principal amount of the notes plus a make-whole premium, together with accrued interest to the redemption date. If the Company redeems the 2.800% Notes on or after May 1, 2020 or the 4.000% Notes on or after March 1, 2025, it will not be required to pay a make-whole premium. In addition, if the Company undergoes a change of control and ratings decline, each as defined in the supplemental indenture, it may be required to repurchase all of the notes at a purchase price equal to 101% of the principal amount of the notes, plus accrued and unpaid interest (including additional interest, if any), up to but not including the repurchase date. The notes rank equally with all of the Company’s other senior unsecured debt and are structurally subordinated to all existing and future indebtedness and other obligations of its subsidiaries. The supplemental indenture contains certain covenants that restrict the Company’s ability to merge, consolidate or sell assets and its (together with its subsidiaries’) ability to incur liens. These covenants are subject to a number of exceptions, including that the Company, and its subsidiaries, may incur certain liens on assets, mortgages or other liens securing indebtedness, if the aggregate amount of such liens does not exceed 3.5 x Adjusted EBITDA, as defined in the supplemental indenture.

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2015
Summary of Derivative Instruments [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments Interest rate swap agreements —Certain of the Company’s foreign subsidiaries have entered into interest rate swap agreements, which have been designated as cash flow hedges, to manage exposure to variability in interest rates on debt. The notional amount and fair value of the interest rate swap agreements were as follows (in thousands): September 30, 2015 December 31, 2014 Local USD Local USD South Africa (Rand) Notional 404,478 29,194 440,614 38,080 Fair Value 3,205 231 1,016 88 Colombia (Colombian Peso) Notional 96,250,000 30,830 100,000,000 41,798 Fair Value 858,788 275 (1,548,688 ) (647 ) As of September 30, 2015 the South African and Colombian agreements were in asset positions, and as of December 31, 2014, the South African agreements were in an asset position and the Colombian agreement was in a liability position. Asset positions were included in Notes receivable and other non-current assets and liability positions were included in Other non-current liabilities on the condensed consolidated balance sheets. Embedded derivative —In connection with the acquisition of communications sites in Nigeria on July 1, 2015, the Company entered into a lease agreement where a portion of the monthly rent to be received is escalated based on an index outside the lessor’s economic environment. The fair value of the portion of the lease tied to the US Consumer Price Index was $14.6 million at the date of acquisition and was recorded in Notes receivable and other non-current assets on the condensed consolidated balance sheets. Treasury rate lock —The Company was amortizing the settlement cost of a treasury rate lock as additional interest expense over the term of the 7.000% Notes. In connection with the redemption of the 7.000% Notes, the Company recognized $2.0 million of the remaining deferred loss on the settlement cost as a loss on retirement of long-term obligations in the condensed consolidated statements of operations. During the three months ended September 30, 2015 and 2014 , the interest rate swap agreements had the following impact on the Company’s condensed consolidated financial statements (in thousands): Three Months Ended September 30, Gain(Loss) Recognized in OCI - Effective Portion Gain(Loss) Effective Portion Location of Gain(Loss) Reclassified from AOCI into Income- Effective Portion Gain(Loss) Recognized Location of Gain(Loss) Recognized in Income - Ineffective Portion 2015 $701 $(178) Interest Expense N/A N/A 2014 $(526) $(578) Interest Expense N/A N/A During the nine months ended September 30, 2015 and 2014 , the interest rate swap agreements and treasury rate lock had the following impact on the Company’s condensed consolidated financial statements (in thousands): Nine Months Ended September 30, Gain(Loss) Recognized in OCI - Effective Portion Gain(Loss) Effective Portion Location of Gain(Loss) Reclassified from AOCI into Income- Effective Portion Gain(Loss) Recognized Location of Gain(Loss) Recognized in Income - Ineffective Portion 2015 $347 $(2,837) Interest Expense/Loss on Retirement of Long-Term Obligations N/A N/A 2014 $(887) $(2,217) Interest Expense N/A N/A As of September 30, 2015 , approximately $0.1 million of the amount related to derivatives designated as cash flow hedges and recorded in Accumulated other comprehensive loss was expected to be reclassified into earnings in the next 12 months. For additional information on the Company’s interest rate swap agreements, see note 7.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	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. Below are the three levels of inputs that may be used to measure fair value: Level 1 Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Items Measured at Fair Value on a Recurring Basis —The fair value of the Company’s financial assets and liabilities that are required to be measured on a recurring basis at fair value is as follows (in thousands): September 30, 2015 Fair Value Measurements Using Assets/Liabilities at Fair Value Level 1 Level 2 Level 3 Assets: Short-term investments (1) $ 14,485 $ 14,485 Interest rate swap agreements $ 506 $ 506 Embedded derivative in lease agreement $ 14,564 $ 14,564 Liabilities: Acquisition-related contingent consideration $ 18,488 $ 18,488 December 31, 2014 Fair Value Measurements Using Assets/Liabilities at Fair Value Level 1 Level 2 Level 3 Assets: Short-term investments (1) $ 6,302 $ 6,302 Interest rate swap agreements $ 88 $ 88 Liabilities: Acquisition-related contingent consideration $ 28,524 $ 28,524 Interest rate swap agreements $ 647 $ 647 (1) Consists of highly liquid investments with original maturities in excess of three months. Interest Rate Swap Agreements The fair value of the Company’s interest rate swap agreements is determined using pricing models with inputs that are observable in the market or can be derived principally from, or corroborated by, observable market data. Fair valuations of the interest rate swap agreements reflect the value of the instrument including the values associated with counterparty risk, the Company’s own credit standing and the value of the net credit differential between the counterparties to the derivative contract. Embedded Derivative in Lease Agreement The fair value of the Company’s embedded derivative is determined using a discounted cash flow approach. This approach takes into consideration Level 3 unobservable inputs including expected future cash flows over the period in which the associated payment is expected to be received and applies a discount factor that captures uncertainties in the future periods associated with the expected payment. Acquisition-Related Contingent Consideration Acquisition-related contingent consideration is initially measured and recorded at fair value as an element of consideration paid in connection with an acquisition with subsequent adjustments recognized in Other operating expenses in the condensed consolidated statements of operations. The Company determines the fair value of acquisition-related contingent consideration, and any subsequent changes in fair value, using a discounted probability-weighted approach. This approach takes into consideration Level 3 unobservable inputs including probability assessments of expected future cash flows over the period in which the obligation is expected to be settled and applies a discount factor that captures the uncertainties associated with the obligation. Changes in the unobservable inputs of Level 3 assets or liabilities could significantly impact the fair value of these assets or liabilities recorded in the accompanying condensed consolidated balance sheets, with the adjustments being recorded in the condensed consolidated statements of operations. As of September 30, 2015 , the Company estimated the value of all potential acquisition-related contingent consideration required payments to be between zero and $26.0 million . During the three months ended September 30, 2015 and 2014 , the fair value of the contingent consideration changed as follows (in thousands): 2015 2014 Balance as of July 1 $ 24,867 $ 31,025 Additions — 106 Settlements (3,408 ) (209 ) Change in fair value 99 (974 ) Foreign currency translation adjustment (3,070 ) (1,794 ) Other (1) — (730 ) Balance as of September 30 $ 18,488 $ 27,424 During the nine months ended September 30, 2015 and 2014 , the fair value of the contingent consideration changed as follows (in thousands): 2015 2014 Balance as of January 1 $ 28,524 $ 31,890 Additions 1,311 512 Settlements (6,761 ) (1,498 ) Change in fair value 99 (1,344 ) Foreign currency translation adjustment (4,685 ) (1,406 ) Other (1) — (730 ) Balance as of September 30 $ 18,488 $ 27,424 (1) In connection with the sale of operations in Panama in September 2014, the buyer assumed the Company’s potential obligations related to additional purchase price consideration. Items Measured at Fair Value on a Nonrecurring Basis Assets Held and Used —The Company’s long-lived assets are recorded at amortized cost and, if impaired, are adjusted to fair value using Level 3 inputs. During the three and nine months ended September 30, 2015 and 2014, the Company did not record any asset impairment charges. Sale of Assets —During the nine months ended September 30, 2014, the Company completed the sale of its operations in Panama and its third-party structural analysis business for an aggregate sale price of $17.9 million , plus a working capital adjustment. At the time of sale, the carrying value of these assets primarily included $8.1 million of property and equipment, $7.8 million of intangible assets and $3.6 million of goodwill. The Company recorded a net impairment charge of $2.2 million in Other operating expenses in the accompanying condensed consolidated statements of operations. There were no items measured at fair value on a nonrecurring basis during the nine months ended September 30, 2015 . Fair Value of Financial Instruments —The Company’s financial instruments for which the carrying value reasonably approximates fair value at September 30, 2015 and December 31, 2014 included cash and cash equivalents, restricted cash, accounts receivable and accounts payable. The Company’s estimates of fair value of its long-term obligations, including the current portion, are based primarily upon reported market values. For long-term debt not actively traded, fair value is estimated using either indicative price quotes or a discounted cash flow analysis using rates for debt with similar terms and maturities. As of September 30, 2015 , the carrying value and fair value of long-term obligations, including the current portion, were $17.0 billion and $17.3 billion , respectively, of which $9.9 billion was measured using Level 1 inputs and $7.4 billion was measured using Level 2 inputs. As of December 31, 2014 , the carrying value and fair value of long-term obligations, including the current portion, were $14.6 billion and $15.0 billion , respectively, of which $9.7 billion was measured using Level 1 inputs and $5.3 billion was measured using Level 2 inputs.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The changes in Accumulated other comprehensive loss for the three months ended September 30, 2015 and 2014 were as follows (in thousands): Unrealized Losses on Cash Flow Hedges Foreign Total Balance as of July 1, 2015 $ (1,333 ) $ (1,227,188 ) $ (1,228,521 ) Other comprehensive income (loss) before reclassifications, net of tax 717 (605,244 ) (604,527 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 145 — 145 Net current-period other comprehensive income (loss) 862 (605,244 ) (604,382 ) Balance as of September 30, 2015 $ (471 ) $ (1,832,432 ) $ (1,832,903 ) Unrealized Losses on Cash Flow Hedges Deferred Loss on the Settlement of the Treasury Rate Lock Foreign Total Balance as of July 1, 2014 $ (1,301 ) $ (2,630 ) $ (246,989 ) $ (250,920 ) Other comprehensive loss before reclassifications, net of tax (514 ) — (253,424 ) (253,938 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 319 200 — 519 Net current-period other comprehensive (loss) income (195 ) 200 (253,424 ) (253,419 ) Balance as of September 30, 2014 $ (1,496 ) $ (2,430 ) $ (500,413 ) $ (504,339 ) The changes in Accumulated other comprehensive loss for the nine months ended September 30, 2015 and 2014 were as follows (in thousands): Unrealized Losses on Cash Flow Hedges Deferred Loss on the Settlement of the Treasury Rate Lock Foreign Total Balance as of January 1, 2015 $ (1,345 ) $ (2,231 ) $ (790,645 ) $ (794,221 ) Other comprehensive loss before reclassifications, net of tax 377 — (1,041,787 ) (1,041,410 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 497 2,231 — 2,728 Net current-period other comprehensive income (loss) 874 2,231 (1,041,787 ) (1,038,682 ) Balance as of September 30, 2015 $ (471 ) $ — $ (1,832,432 ) $ (1,832,903 ) Unrealized Losses on Cash Flow Hedges Deferred Loss on the Settlement of the Treasury Rate Lock Foreign Total Balance as of January 1, 2014 $ (1,869 ) $ (3,029 ) $ (306,322 ) $ (311,220 ) Other comprehensive loss before reclassifications, net of tax (969 ) — (194,091 ) (195,060 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 1,342 599 — 1,941 Net current-period other comprehensive income (loss) 373 599 (194,091 ) (193,119 ) Balance as of September 30, 2014 $ (1,496 ) $ (2,430 ) $ (500,413 ) $ (504,339 ) During the nine months ended September 30, 2015 , $2.0 million related to the deferred loss on the settlement of the treasury rate lock was reclassified from Accumulated other comprehensive loss into Gain (loss) on retirement of long-term obligations in connection with redemption of the 7.000% Notes. The remaining losses on cash flow hedges have been reclassified into Interest expense in the accompanying condensed consolidated statements of operations and the associated tax effect of less than $0.1 million for each of the three and nine months ended September 30, 2015 and 2014 is included in Income tax provision.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income Taxes	Income Taxes The Company provides for income taxes at the end of each interim period based on the estimated effective tax rate for the full fiscal year. Cumulative adjustments to the Company’s estimate are recorded in the interim period in which a change in the estimated annual effective tax rate is determined. As a REIT, the Company continues to be subject to income taxes on the income of its TRSs and income taxation in foreign jurisdictions where it conducts international operations. Under the provisions of the Internal Revenue Code of 1986, as amended, the Company may deduct amounts distributed to stockholders against the income generated in its QRSs. The Company is able to offset income in both its TRSs and QRSs by utilizing their respective net operating losses. In 2013, the Company acquired MIP Tower Holdings LLC (“MIPT”), which had been organized and qualified as a REIT. The Company filed a tax election pursuant to which MIPT no longer operates as a separate REIT for federal and state income tax purposes, effective July 25, 2015. In connection with this and related elections, the Company incurred a one-time cash tax charge of approximately $93.0 million and a one-time deferred income tax benefit of $5.4 million in the third quarter of 2015. The Company 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. As of September 30, 2015 and December 31, 2014, the total amount of unrecognized tax benefits that would impact the effective tax rate, if recognized, was approximately $26.5 million and $31.9 million , respectively. The amount of unrecognized tax benefits during the three and nine months ended September 30, 2015 includes additions to the Company’s existing tax positions, offset by foreign currency fluctuations and the expiration of the statute of limitations in certain jurisdictions. The Company expects the unrecognized tax benefits to change over the next 12 months if certain tax matters ultimately settle with the applicable taxing jurisdiction during this timeframe, as described in note 14 to the Company’s consolidated financial statements included in the 2014 Form 10-K. The impact of the amount of these changes to previously recorded uncertain tax positions could range from zero to $5.1 million . The Company recorded penalties and income tax-related interest expense during the three and nine months ended September 30, 2015 of $0.7 million and $2.3 million , respectively, and during the three and nine months ended September 30, 2014 of $1.8 million and $4.8 million , respectively. In addition, due to the expiration of the statute of limitations in certain jurisdictions, the Company reduced its liability for penalties and income tax-related interest expense related to uncertain tax positions during each of the three and nine months ended September 30, 2015 by $3.1 million and during each of the three and nine months ending September 30, 2014 by $1.4 million . As of September 30, 2015 and December 31, 2014, the total amount of accrued income tax related interest and penalties included in Other non-current liabilities in the condensed consolidated balance sheets was $19.4 million and $24.9 million , respectively.

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2015
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Company recognized stock-based compensation expense during the three and nine months ended September 30, 2015 of $18.3 million and $72.3 million , respectively, and stock-based compensation expense during the three and nine months ended September 30, 2014 of $18.3 million and $61.7 million , respectively. The Company capitalized stock-based compensation expense of $0.5 million and $1.6 million during the three and nine months ended September 30, 2015 , respectively, and $0.4 million and $1.2 million during the three and nine months ended September 30, 2014 , respectively, as property and equipment. Summary of Stock-Based Compensation Plans —The Company maintains equity incentive plans that provide for the grant of stock-based awards to its directors, officers and employees. The 2007 Equity Incentive Plan (the “2007 Plan”) provides for the grant of non-qualified and incentive stock options, as well as restricted stock units, restricted stock and other stock-based awards. Exercise prices in the case of non-qualified and incentive stock options are not less than the fair value of the underlying common stock on the date of grant. Equity awards typically vest ratably over various periods, generally four years for time-based restricted stock units (“RSUs”) and stock options and three years for performance-based restricted stock units (“PSUs”). Stock options generally expire ten years from the date of grant. As of September 30, 2015 , the Company had the ability to grant stock-based awards with respect to an aggregate of 11.7 million shares of common stock under the 2007 Plan. The Company’s Compensation Committee adopted a death, disability and retirement benefits program, which applies to equity awards granted on or after January 1, 2013 and 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, for grants made on or after January 1, 2013, the Company recognizes compensation expense for stock options and 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; and recognizes compensation expense for PSUs over the three -year vesting period, subject to adjustment based on the date the employee becomes eligible for such retirement benefits. Stock Options —The Company’s option activity for the nine months ended September 30, 2015 was as follows: Number of Options Outstanding as of January 1, 2015 6,508,435 Granted 2,004,100 Exercised (441,626 ) Forfeited (105,226 ) Expired (1,475 ) Outstanding as of September 30, 2015 7,964,208 The fair value of each option granted during the nine months ended September 30, 2015 was estimated on the date of grant using the Black-Scholes option pricing model based on the assumptions noted in the table below. Key assumptions used to apply this pricing model are as follows: Range of risk-free interest rate 1.32%-1.62% Weighted average risk-free interest rate 1.62 % Expected life of option grants 4.5 years Range of expected volatility of underlying stock price 21.09%-21.20% Weighted average expected volatility of underlying stock price 21.09 % Range of expected annual dividend yield 1.50%-1.85% The weighted average grant date fair value per share during the nine months ended September 30, 2015 was $15.09 . As of September 30, 2015 , total unrecognized compensation expense related to unvested stock options was $33.7 million and is expected to be recognized over a weighted average period of approximately two years . Restricted Stock Units and Performance-Based Restricted Stock Units— The Company’s RSU and PSU activity for the nine months ended September 30, 2015 was as follows: RSUs PSUs (1) Outstanding as of January 1, 2015 1,758,817 — Granted 692,340 23,379 Vested (688,811 ) — Forfeited (93,746 ) — Outstanding as of September 30, 2015 1,668,600 23,379 (1) Represents the target number of shares issuable at the end of the three -year performance cycle attributable to the first year’s performance period. Restricted Stock Units— As of September 30, 2015 , total unrecognized compensation expense related to unvested RSUs granted under the 2007 Plan was $87.4 million and is expected to be recognized over a weighted average period of approximately two years . Performance-Based Restricted Stock Units— During the nine months ended September 30, 2015 , the Compensation Committee granted an aggregate of 70,135 PSUs to its executive officers and established the performance metric for this award. Threshold, target and maximum parameters were established for the metric for each year in the three -year performance period, and will be used to calculate the number of shares that will be issuable when the award vests, which may range from zero to 200 percent of the target amount. At the end of the three -year performance period, the number of shares that are earned and vest will depend on the degree of achievement against the pre-established performance goal. PSUs that have been earned over the performance period will be paid out in common stock at the end of the performance period, subject generally to the executive’s continued employment and will accrue dividend equivalents prior to vesting, which will be paid out only in respect of shares actually earned and vested. As the performance metric is tied to year-over-year growth and actual results for the metric will not be determined until the end of each respective fiscal year, the Company is unable to determine the annual target for the second and third years of the performance period for this award at this time. Accordingly, an aggregate of 46,756 PSUs granted on March 10, 2015 are not included in the table above. The grant date fair value per share of the PSUs for which terms have been established was $94.57 . During the three and nine months ended September 30, 2015 , the Company recorded $0.8 million and $1.5 million , respectively, in stock-based compensation expense for equity awards in which the performance goals have been established and are probable of being achieved. The remaining unrecognized compensation expense related to these awards at September 30, 2015 was $1.3 million based on the Company’s current assessment of the probability of achieving the performance goals. The weighted-average period over which the cost will be recognized is approximately one year . Employee Stock Purchase Plan— The Company maintains an employee stock purchase plan (“ESPP”) pursuant to which eligible employees may purchase shares of the Company’s common stock on the last day of each bi-annual offering period at a 15% discount of the lower of the closing market value on the first or last day of such offering period. The offering periods run from June 1 through November 30 and from December 1 through May 31 of each year. During the nine months ended September 30, 2015 , employee contributions were accumulated to purchase approximately 66,000 shares under the ESPP. Key assumptions used to apply the Black-Scholes pricing model for shares purchased through the ESPP during the nine months ended September 30, 2015 , which resulted in a fair value per share of $16.40 , were as follows: Approximate risk-free interest rate 0.06 % Expected life of shares 6 months Expected volatility of underlying stock price over the option period 13.91 % Expected annual dividend yield 1.85 %

Equity

Equity	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Equity	Equity Common Stock Offering —On March 3, 2015, the Company completed a registered public offering of 23,500,000 shares of its common stock, par value $0.01 per share, at $97.00 per share. On March 5, 2015, the Company issued an additional 2,350,000 shares of common stock in connection with the underwriters’ exercise in full of their over-allotment option. Aggregate net proceeds were approximately $2.44 billion after deducting commissions and estimated expenses. The Company used the net proceeds from this offering to fund a portion of the Verizon Transaction. Series B Preferred Stock Offering —On March 3, 2015, the Company completed a registered public offering of 12,500,000 depositary shares, each representing a 1/10th interest in a share of its 5.50% Mandatory Convertible Preferred Stock, Series B, par value $0.01 per share (the “Series B Preferred Stock”), at $100.00 per depositary share. On March 5, 2015, the Company issued an additional 1,250,000 depositary shares in connection with the underwriters’ exercise in full of their over-allotment option. Aggregate net proceeds were approximately $1.34 billion after deducting commissions and estimated expenses. The Company used the net proceeds from this offering to fund a portion of the Verizon Transaction. On March 3, 2015, upon receipt of the proceeds of this offering and the common stock offering described above, the Company terminated the commitment letter dated February 5, 2015 with Goldman Sachs Bank USA and Goldman Sachs Lending Partners LLC entered into in connection with the Verizon Transaction. Unless converted or redeemed earlier, each share of the Series B Preferred Stock will convert automatically on February 15, 2018, into between 8.5911 and 10.3093 shares of common stock, depending on the applicable market value of the common stock and subject to anti-dilution adjustments. Subject to certain restrictions, at any time prior to February 15, 2018, holders of the Series B Preferred Stock may elect to convert all or a portion of their shares into common stock at the minimum conversion rate then in effect. Dividends on shares of the Series B Preferred Stock are payable on a cumulative basis when, as and if declared by the Company’s Board of Directors at an annual rate of 5.50% on the liquidation preference of $1,000.00 per share (and, correspondingly, $100.00 per share with respect to the depositary shares) on February 15, May 15, August 15 and November 15 of each year, commencing on May 15, 2015 to, and including, February 15, 2018. The Company may pay dividends in cash or, subject to certain limitations, in shares of common stock or any combination of cash and shares of common stock. The terms of the Series B Preferred Stock provide that, unless full cumulative dividends have been paid or set aside for payment on all outstanding Series B Preferred Stock for all prior dividend periods, no dividends may be declared or paid on common stock. Series A Preferred Stock —The Company has 6,000,000 shares outstanding of its 5.25% Mandatory Convertible Preferred Stock, Series A, par value $0.01 per share (the “Series A Preferred Stock” and, together with the Series B Preferred Stock, the “Mandatory Convertible Preferred Stock”). Unless converted earlier, each share of the Series A Preferred Stock will automatically convert on May 15, 2017, into between 0.9174 and 1.1468 shares of common stock, depending on the applicable market value of the common stock and subject to anti-dilution adjustments. Subject to certain restrictions, at any time prior to May 15, 2017, holders of the Series A Preferred Stock may elect to convert all or a portion of their shares into common stock at the minimum conversion rate then in effect. Dividends on shares of the Series A Preferred Stock are payable on a cumulative basis when, as and if declared by the Company’s Board of Directors at an annual rate of 5.25% on the liquidation preference of $100.00 per share, on February 15, May 15, August 15 and November 15 of each year, commencing on August 15, 2014 to, and including, May 15, 2017. Sales of Equity Securities— The Company receives proceeds from sales of its equity securities pursuant to the ESPP and upon exercise of stock options granted under its equity incentive plans. During the nine months ended September 30, 2015 , the Company received an aggregate of $29.3 million in proceeds upon exercises of stock options and from the ESPP. Distributions —During the nine months ended September 30, 2015 , the Company declared or paid the following cash distributions: Declaration Date Payment Date Record Date Distribution per share Aggregate Payment Amount (in millions) Common Stock December 2, 2014 January 13, 2015 December 16, 2014 $ 0.38 $ 150.7 March 5, 2015 April 28, 2015 April 10, 2015 $ 0.42 $ 177.7 May 21, 2015 July 16, 2015 June 17, 2015 $ 0.44 $ 186.2 September 10, 2015 October 7, 2015 September 23, 2015 $ 0.46 $ 194.8 Series A Preferred Stock December 2, 2014 February 16, 2015 February 1, 2015 $ 1.3125 $ 7.9 April 14, 2015 May 15, 2015 May 1, 2015 $ 1.3125 $ 7.9 July 15, 2015 August 17, 2015 August 1, 2015 $ 1.3125 $ 7.9 Series B Preferred Stock April 14, 2015 May 15, 2015 May 1, 2015 $ 11.1528 $ 15.3 July 15, 2015 August 17, 2015 August 1, 2015 $ 13.7500 $ 18.9 The Company accrues distributions on unvested restricted stock units granted subsequent to January 1, 2012, which are payable upon vesting. As of September 30, 2015 , the amount accrued for distributions payable related to unvested restricted stock units was $4.3 million . During the nine months ended September 30, 2015 , the Company paid $1.2 million of distributions upon the vesting of restricted stock units. To maintain its qualification for taxation as a REIT, the Company expects to continue paying distributions, the amount, timing and frequency of which will be determined, and subject to adjustment, by the Company’s Board of Directors.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share 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 shares issuable upon (i) the vesting of restricted stock awards, (ii) exercise of stock options and (iii) conversion of the Company’s Mandatory Convertible Preferred Stock. Dilutive common share equivalents also include the dilutive impact of the ALLTEL transaction (see note 13). The Company uses the treasury stock method to calculate the effect of its outstanding restricted stock awards and stock options and uses the if-converted method to calculate the effect of its outstanding Mandatory Convertible Preferred Stock. The following table sets forth basic and diluted net income per common share computational data for the three and nine months ended September 30, 2015 and 2014 (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Net income attributable to American Tower Corporation stockholders $ 102,999 $ 207,593 $ 452,372 $ 644,523 Dividends on preferred stock (26,781 ) (7,700 ) (63,382 ) (12,075 ) Net income attributable to American Tower Corporation common stockholders 76,218 199,893 388,990 632,448 Basic weighted average common shares outstanding 423,375 396,243 417,280 395,758 Dilutive securities 3,852 4,154 4,072 4,048 Diluted weighted average common shares outstanding 427,227 400,397 421,352 399,806 Basic net income attributable to American Tower Corporation common stockholders per common share $ 0.18 $ 0.50 $ 0.93 $ 1.60 Diluted net income attributable to American Tower Corporation common stockholders per common share $ 0.18 $ 0.50 $ 0.92 $ 1.58 Shares Excluded From Dilutive Effect The following shares were not included in the computation of diluted earnings per share because the effect would be anti-dilutive (in thousands, on a weighted average basis): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Restricted stock awards — — — — Stock options 1,996 1 1,472 2,255 Preferred stock 17,368 6,688 14,724 3,473

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation The Company periodically becomes involved in various claims, lawsuits and proceedings that are incidental to its business. In the opinion of Company management, after consultation with counsel, there are no matters currently pending that would, in the event of an adverse outcome, materially impact the Company’s consolidated financial position, results of operations or liquidity. Lease Obligations Tenant Leases —As part of the Verizon Transaction, the Company entered into leases or subleases with Verizon with respect to 11,448 communications sites with an initial non-cancellable term of ten years . In addition, the Company assumed the rights under the tenant leases that were in place on such sites at the time of the transaction. At the time of the transaction, the total estimated future minimum rental receipts under the non-cancellable Verizon leases and assumed third-party leases was approximately $3.0 billion and was expected to be recognized over an average period of approximately 10 years . Lease Obligations —In connection with the Verizon Transaction, the Company assumed the interest in and obligations under certain ground leases. Many of the leases contain renewal options with specified increases in lease payments upon exercise of the renewal option. Escalation clauses present in operating leases, excluding those tied to the Consumer Price Index or other inflation-based indices, are recognized on a straight-line basis over the non-cancellable term of the leases. Future minimum rental payments under non-cancellable operating leases include payments for certain renewal periods at the Company’s option because failure to renew could result in a loss of the applicable communications sites and related revenues from tenant leases, thereby making it reasonably assured that the Company will renew the leases. At the time of the transaction, the Company’s future minimum rental payments under non-cancellable operating leases, including certain renewal periods related to the Verizon communications sites, was approximately $2.2 billion and was expected to be recognized over an average period of approximately 17 years . Commitments Verizon Transaction —On March 27, 2015, the Company entered into an agreement with various operating entities of Verizon that provides for the lease, sublease or management of 11,285 wireless communications sites from Verizon commencing March 27, 2015. The average term of the lease or sublease for all sites at the inception of the agreement was approximately 28 years, assuming renewals or extensions of the underlying ground leases for the sites. The Company has the option to purchase the leased sites in tranches, subject to the applicable lease, sublease or management right upon its scheduled expiration. Each tower is assigned to an annual tranche, ranging from 2034 to 2047, which represents the outside expiration date for the sublease rights to the towers in each tranche. The purchase price for each tranche is a fixed amount stated in the lease for such tranche plus the fair market value of certain alterations made to the related towers. The aggregate purchase option price for the towers leased and subleased is approximately $5.0 billion . Verizon will occupy the sites as a tenant for an initial term of ten years with eight optional successive five -year terms; each such term shall be governed by standard master lease agreement terms established as a part of the transaction. AT&T Transaction —The Company has an agreement with SBC Communications Inc., a predecessor entity to AT&T Inc. (“AT&T”), that currently provides for the lease or sublease of approximately 2,400 towers from AT&T with the lease commencing between December 2000 and August 2004. Substantially all of the towers are part of the Company’s securitization transaction completed in March 2013. The average term of the lease or sublease for all sites at the inception of the agreement was approximately 27 years , assuming renewals or extensions of the underlying ground leases for the sites. The Company has the option to purchase the sites subject to the applicable lease or sublease upon its expiration. Each tower is assigned to an annual tranche, ranging from 2013 to 2032, which represents the outside expiration date for the sublease rights to that tower. The purchase price for each site is a fixed amount stated in the lease for that site plus the fair market value of certain alterations made to the related tower by AT&T. As of September 30, 2015 , the Company has purchased an aggregate of 31 of the subleased towers upon expiration of the applicable agreement. The aggregate purchase option price for the remaining towers leased and subleased is approximately $691.7 million and will accrete at a rate of 10% per annum through the applicable expiration of the lease or sublease of a site. For all such sites purchased by the Company prior to June 30, 2020, AT&T will continue to lease the reserved space at the then-current monthly fee which shall escalate in accordance with the standard master lease agreement for the remainder of AT&T’s tenancy. Thereafter, AT&T shall have the right to renew such lease for up to four successive five -year terms. For all such sites purchased by the Company subsequent to June 30, 2020, AT&T has the right to continue to lease the reserved space for successive one -year terms at a rent equal to the lesser of the agreed upon market rate and the then-current monthly fee, which is subject to an annual increase based on changes in the Consumer Price Index. ALLTEL Transaction —In December 2000, the Company entered into an agreement with ALLTEL, a predecessor entity to Verizon Wireless, to acquire towers through a 15 -year sublease agreement. Pursuant to the agreement, as amended, with Verizon Wireless, the Company acquired rights to approximately 1,800 towers in tranches between April 2001 and March 2002. The Company has the option to purchase each tower at the expiration of the applicable sublease, which will occur in tranches between April 2016 and March 2017 based on the original closing date for such tranche of towers. The purchase price per tower as of the original closing date was $27,500 and will accrete at a rate of 3% per annum through the expiration of the applicable sublease. The aggregate purchase option price for the subleased towers is approximately $74.7 million as of September 30, 2015 . At the expiration of the sublease, the purchase price would be payable in cash or, at Verizon Wireless’s or its assignee’s option, as applicable, with 769 shares of the Company’s common stock per tower, which would be valued at approximately $119.8 million in the aggregate based on the closing price at September 30, 2015 . Other Contingencies —The Company is subject to income tax and other taxes in the geographic areas where it operates, and periodically receives notifications of audits, assessments or other actions by taxing authorities. The Company evaluates the circumstances of each notification based on the information available and records a liability for any potential outcome that is probable or more likely than not unfavorable if the liability is also reasonably estimable. On January 21, 2014, the Company received an income tax assessment in the amount of 22.6 billion INR (approximately $369.0 million on the date of assessment), asserting tax liabilities arising out of a transfer pricing review of transactions by Essar Telecom Infrastructure Private Limited. The Company challenged the assessment before India’s Income Tax Appellate Tribunal, which issued a decision in the Company’s favor on April 15, 2015, finding, consistent with precedent from the Bombay High Court, that no income tax obligation arose as a result of the issuance of share capital.

Acquisitions and Other Transact

Acquisitions and Other Transactions	9 Months Ended
	Sep. 30, 2015
Business Combination, Description [Abstract]
Acquisitions and Other Transactions	Acquisitions and Other Transactions 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. The effect of measurement period adjustments to the estimated fair value is reflected as if the adjustments had been completed on the acquisition date. The impact of all changes that do not qualify as measurement period adjustments are included in current period earnings. If the actual results differ from the estimates and judgments used in these fair values, the amounts recorded in the condensed consolidated financial statements could be subject to a possible impairment of the intangible assets or goodwill, or require acceleration of the amortization expense of intangible assets in subsequent periods. During the nine months ended September 30, 2015 , the Company made certain measurement period adjustments related to several acquisitions consummated in 2014 and therefore retrospectively adjusted the fair value of the assets acquired and liabilities assumed in the condensed consolidated balance sheet as of December 31, 2014 . 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 condensed consolidated statements of operations for the three and nine months ended September 30, 2015 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 be dependent 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 2015 acquisitions and the Verizon Transaction on the Company’s revenues and gross margin for the three months ended September 30, 2015 was approximately $172.8 million and $76.8 million , respectively, and the estimated aggregate impact for the nine months ended September 30, 2015 was approximately $289.1 million and $132.9 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 have not been reflected, as the amounts attributable to transactions are not comparable. 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 non-recurring 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 condensed consolidated statements of operations. During the three and nine months ended September 30, 2015 and 2014 , the Company recorded the following acquisition and merger related expenses and integration costs (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Acquisition and merger related expenses (1) $ 8,587 $ 4,051 $ 16,574 $ 18,657 Integration costs $ 5,938 $ 5,205 $ 12,218 $ 10,891 (1) Acquisition and merger related expenses for the nine months ended September 30, 2015 do not reflect approximately $9.9 million of transaction costs related to the Verizon Transaction as these costs have been capitalized as part of the assets’ fair value. Verizon Transaction On March 27, 2015, the Company completed its acquisition of the exclusive right to lease, acquire or otherwise operate and manage 11,448 wireless communications sites from Verizon for approximately $5.053 billion in cash 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, subject to certain post-closing adjustments. The Company, through its wholly-owned subsidiary, leased or subleased from certain Verizon subsidiaries 11,285 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. The total consideration allocated to this element of the overall transaction was $4.964 billion , which included approximately $9.9 million of transaction costs. 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 of $99.0 million is reflected below in “2015 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 rent increases of 2% . The Company funded the Verizon Transaction with (i) proceeds from its concurrent registered public offerings of its common stock and Series B Preferred Stock, (ii) borrowings under the Company’s revolving credit facilities and (iii) cash on hand. The Company included the Verizon Transaction in the unaudited pro forma financial results included herein as if the capital lease began on January 1, 2014. Management relied on various estimates and assumptions due to the fact that Verizon did not operate the sites as a business and the sites were utilized primarily by Verizon as a component of its network infrastructure. The following table summarizes the allocation of consideration transferred for the 11,285 communications sites under the Master Prepaid Lease (in thousands). Balances are reflected in the accompanying condensed consolidated balance sheets as of September 30, 2015 and represent the asset balances of the capital lease. Current assets $ 6,079 Non-current assets 144,921 Property and equipment 2,044,900 Intangible assets (1): Customer-related intangible assets 1,856,972 Network location intangible assets 1,172,622 Current liabilities (10,747 ) Other non-current liabilities (2) (250,530 ) Fair value of consideration transferred (3) $ 4,964,217 (1) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . (2) Primarily represents liabilities recorded for asset retirement obligations. (3) Includes approximately $9.9 million of transaction costs, which have been capitalized as part of the assets’ fair value, $5.6 million of which was paid during the nine months ended September 30, 2015 . The acquisitions described below under “2015 Acquisitions” and “2014 Acquisitions” are accounted for as business combinations and are consistent with the Company’s strategy to expand in selected geographic areas. 2015 Acquisitions Airtel Acquisition —On July 1, 2015, the Company acquired 4,699 communications sites in Nigeria from certain of Bharti Airtel Limited’s subsidiaries (“Airtel”), and subsequently acquired one additional site, pursuant to its previously announced agreement for a total purchase price of approximately $1.109 billion , including value added tax. Of this purchase price, $806.5 million was paid during the three months ended September 30, 2015 , with the remainder to be paid prior to January 15, 2016. The purchase price is subject to post-closing adjustments. TIM Acquisition— On April 29, 2015, the Company acquired 4,176 communications sites from TIM pursuant to its previously announced agreement for a purchase price of approximately 1.9 billion BRL (approximately $644.3 million at the date of acquisition). On September 30, 2015, the Company acquired an additional 1,125 communications sites from TIM for an initial aggregate purchase price of 516.9 million BRL (approximately $130.9 million at the date of acquisition). The purchase prices are subject to post-closing adjustments. Pursuant to the terms of the agreement, the Company has the ability to purchase the remaining sites as they become available through October 2016. Following these closings, the amount of the letters of credit with Banco Santander was reduced to approximately 47.8 million BRL (approximately $12.0 million ), corresponding to certain obligations related to the Company’s acquisition agreement. Other International Acquisitions —During the nine months ended September 30, 2015 , the Company acquired a total of 399 communications sites and related assets in Brazil, India and Uganda for an aggregate purchase price of $16.2 million , which was satisfied with cash consideration and by the issuance of credits to be applied against trade accounts receivable. The purchase prices are subject to post-closing adjustments. U.S. Acquisitions —During the nine months ended September 30, 2015 , the Company acquired a total of 199 communications sites and equipment, as well as three property interests, in the United States for an aggregate purchase price of $128.7 million (including $1.3 million for the estimated fair value of contingent consideration). Included in these sites are the 163 communications sites acquired as part of the Verizon Transaction, described above. The purchase prices are subject to post-closing adjustments. The following table summarizes the preliminary allocation of the purchase price for the fiscal year 2015 acquisitions based upon their estimated fair value at the date of acquisition (in thousands). Balances are reflected in the accompanying condensed consolidated balance sheet as of September 30, 2015 . Airtel TIM Other International U.S. Current assets $ 15,828 $ — $ — $ 179 Non-current assets 69,224 — 324 — Property and equipment 414,065 259,945 8,762 30,554 Intangible assets (1): Customer-related intangible assets 232,350 361,829 3,537 50,225 Network location intangible assets 309,902 117,084 3,178 31,464 Current liabilities (4,246 ) — — (336 ) Other non-current liabilities (12,507 ) (24,338 ) (333 ) (3,040 ) Net assets acquired 1,024,616 714,520 15,468 109,046 Goodwill (2) 84,035 60,696 700 19,677 Fair value of net assets acquired 1,108,651 775,216 16,168 128,723 Debt assumed — — — — Purchase Price $ 1,108,651 $ 775,216 $ 16,168 $ 128,723 (1) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . (2) Goodwill was allocated to the Company’s rental and management segments. The Company expects goodwill recorded in its domestic rental and management segment will be deductible for tax purposes. The Company expects goodwill recorded in its international rental and management segment will not be deductible for tax purposes, except for in India, where goodwill is expected to be deductible. 2014 Acquisitions BR Towers Acquisition —On November 19, 2014, the Company completed the acquisition of 100% of the equity interests of BR Towers. At closing, BR Towers owned 2,504 towers and four property interests, as well as the exclusive use rights for 2,113 additional towers and 43 property interests in Brazil. The Company completed the acquisition for an estimated preliminary purchase price of approximately $568.9 million , which was subsequently reduced to approximately $558.7 million during the nine months ended September 30, 2015 . In addition, the Company paid approximately $61.1 million to acquire all outstanding preferred equity and assumed approximately $261.1 million of BR Towers’ existing indebtedness. As of September 30, 2015 , the remaining balance of the debt assumed was $82.6 million . Richland Acquisition —On April 3, 2014, the Company, through one of its wholly-owned subsidiaries, acquired entities holding a portfolio of 59 communications sites, which at the time of acquisition were leased primarily to radio and television broadcast tenants, and four property interests in the United States from Richland Properties LLC and other related entities (“Richland”) for an aggregate purchase price of $189.4 million , which was subsequently reduced to $188.9 million during the nine months ended September 30, 2015 . In addition, the Company assumed $196.5 million of Richland’s existing indebtedness, which it repaid in June 2014. Other International Acquisitions —During the year ended December 31, 2014, the Company acquired 159 additional communications sites and related assets in Brazil, Ghana, Mexico and Uganda, for an aggregate purchase price of $28.3 million (including value added tax of $1.2 million ). The Company also acquired 299 communications sites in Mexico for a purchase price of $40.3 million (including value added tax of $5.6 million ), which reflected approximately $3.4 million of net liabilities assumed. Total purchase price was satisfied by the issuance of approximately $36.3 million of credits to be applied against trade accounts receivable and cash consideration of approximately $4.0 million . The allocation of the purchase price for these acquisitions was finalized during the year ended December 31, 2014. Other U.S. Acquisitions —During the year ended December 31, 2014, the Company acquired 184 additional communications sites and equipment, as well as six property interests, in the United States for an aggregate purchase price of $180.8 million (including $6.3 million for the estimated fair value of contingent consideration). The purchase prices are subject to post-closing adjustments. The following table summarizes the updated allocation of the purchase price for the fiscal year 2014 acquisitions based upon their estimated fair value at the date of acquisition (in thousands). Balances are reflected in the accompanying condensed consolidated balance sheets herein. BR Towers Richland (1) Other U.S. Current assets $ 31,568 $ 8,583 $ 332 Non-current assets 9,365 — 1,041 Property and equipment 135,916 154,899 38,092 Intangible assets (2): Customer-related intangible assets 495,151 186,455 88,490 Network location intangible assets 135,549 3,409 38,470 Other intangible assets 33,095 — — Current liabilities (24,012 ) (3,635 ) (1,997 ) Other non-current liabilities (101,814 ) (2,922 ) (1,675 ) Net assets acquired 714,818 346,789 162,753 Goodwill (3) 166,097 44,128 18,069 Fair value of net assets acquired 880,915 390,917 180,822 Debt assumed (4) (261,136 ) (201,999 ) — Preferred stock outstanding (61,056 ) — — Purchase Price $ 558,723 $ 188,918 $ 180,822 (1) The allocation of the purchase price was finalized during the nine months ended September 30, 2015 . (2) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . Other intangible assets are amortized on a straight-line basis over the life of the lease, which is a period of 11 years . (3) Goodwill was allocated to the Company’s rental and management segments, and the Company expects goodwill recorded will be deductible for tax purposes except for goodwill associated with BR Towers, where goodwill is expected to be partially deductible. (4) Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Assumed Richland debt included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million . The fair value adjustments were based primarily on reported market values using Level 2 inputs. The following table summarizes the preliminary allocation of the purchase price paid and the amounts of assets acquired and liabilities assumed for the fiscal year 2014 acquisitions based upon their estimated fair value at the date of acquisition (in thousands). Balances are reflected in the consolidated balance sheets in the 2014 Form 10-K. BR Towers Richland Other U.S. Current assets $ 31,832 $ 8,583 $ 797 Non-current assets 9,135 — — Property and equipment 141,422 185,777 38,413 Intangible assets (1): Customer-related intangible assets 495,279 169,452 89,990 Network location intangible assets 136,233 1,700 39,470 Other intangible assets 37,664 — — Current liabilities (23,930 ) (3,635 ) (1,997 ) Other non-current liabilities (101,508 ) (2,922 ) (1,675 ) Net assets acquired 726,127 358,955 164,998 Goodwill (2) 164,955 32,423 15,824 Fair value of net assets acquired 891,082 391,378 180,822 Debt assumed (3) (261,136 ) (201,999 ) — Preferred stock outstanding (61,056 ) — — Purchase Price $ 568,890 $ 189,379 $ 180,822 (1) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . Other intangible assets are amortized on a straight-line basis over the life of the lease, which is a period of 11 years . (2) Goodwill was allocated to the Company’s rental and management segments, and the Company expects goodwill recorded will be deductible for tax purposes except for goodwill associated with BR Towers where goodwill is expected to be partially deductible. (3) Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Richland debt assumed included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million . The fair value adjustments were based primarily on reported market values using Level 2 inputs. Pro Forma Consolidated Results The following table presents the unaudited pro forma financial results as if the 2015 acquisitions, as well as the Verizon Transaction described above, had occurred on January 1, 2014 and the 2014 acquisitions had occurred on January 1, 2013 (in thousands, except per share data). Management relied on various estimates and assumptions due to the fact that some of the transactions never operated as a business and were utilized solely by the seller as a component of their network infrastructure. As a result, historical operating results may not be available. The pro forma results do not include any anticipated cost synergies, costs or other integration impacts. Accordingly, such pro forma amounts are not necessarily indicative of the results that actually would have occurred had the transactions been completed on the dates indicated, nor are they indicative of the future operating results of the Company. Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Pro forma revenues $ 1,243,347 $ 1,262,421 $ 3,749,564 $ 3,739,837 Pro forma net income attributable to American Tower Corporation common stockholders $ 76,489 $ 139,673 $ 356,060 $ 453,520 Pro forma net income per common share amounts: Basic net income attributable to American Tower Corporation common stockholders $ 0.18 $ 0.33 $ 0.84 $ 1.08 Diluted net income attributable to American Tower Corporation common stockholders $ 0.18 $ 0.33 $ 0.83 $ 1.07 Acquisition-Related Contingent Consideration The Company may be required to pay additional consideration under certain agreements for the acquisition of communications sites if specific conditions are met or events occur. In Colombia and Ghana, the Company may be required to pay additional consideration upon the conversion of certain barter agreements with other wireless carriers to cash-paying lease agreements. In the United States, the Company may be required to pay additional consideration if certain pre-designated tenant leases commence during a specified period of time. A summary of the value of the Company’s contingent consideration is as follows (in thousands): Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 Maximum potential value (1) Estimated value at September 30, 2015 (2) Additions (3) Settlements Change in Fair Value Additions (3) Settlements Change in Fair Value Colombia $ 22,642 $ 15,123 $ — $ — $ — $ — $ — $ — Costa Rica — — — (175 ) — — (1,898 ) — Ghana 577 577 — — 99 — — 99 United States 2,788 2,788 — (3,233 ) — 1,311 (4,863 ) — Total $ 26,007 $ 18,488 $ — $ (3,408 ) $ 99 $ 1,311 $ (6,761 ) $ 99 (1) The maximum potential value is based on exchange rates at September 30, 2015 . The minimum value could be zero . (2) Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015 . (3) Based on preliminary acquisition accounting upon closing of certain acquisitions during the three and nine months ended September 30, 2015 . For more information regarding contingent consideration, see note 7.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2015
Segment Reporting, Measurement Disclosures [Abstract]
Business Segments	Business Segments The Company operates its business in three reportable segments, (i) domestic rental and management, (ii) international rental and management and (iii) network development services. The Company’s primary business is leasing space on multitenant 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. This business is referred to as the Company’s rental and management operations and is comprised of domestic and international segments, which, as of September 30, 2015 , consisted of the following: • Domestic: rental and management operations in the United States; and • International: rental and management operations in Brazil, Chile, Colombia, Costa Rica, Germany, Ghana, India, Mexico, Nigeria, Peru, South Africa and Uganda. The Company has applied the aggregation criteria to operations within the international rental and management operating segments on a basis consistent with management’s review of information and performance evaluation. The Company’s network development services segment offers tower-related services in the United States, including site acquisition, zoning and permitting services and structural analysis services, which primarily support its site leasing business and the addition of new tenants and equipment on its sites. The network development services segment is a strategic business unit that offers different services from the rental and management operating segments and requires different resources, skill sets and marketing strategies. The accounting policies applied in compiling segment information below are similar to those described in note 1 to the Company’s consolidated financial statements included in the 2014 Form 10-K. Among other factors, in evaluating financial performance in each business segment, management uses segment gross margin and segment operating profit. The Company defines segment gross margin as segment revenue less segment operating expenses excluding stock-based compensation expense recorded in costs of operations; Depreciation, amortization and accretion; Selling, general, administrative and development expense; and Other operating expenses. The Company defines segment operating profit as segment gross margin less Selling, general, administrative and development expense attributable to the segment, excluding stock-based compensation expense and corporate expenses. For reporting purposes, the international rental and management segment gross margin and segment operating profit also include Interest income, TV Azteca, net. These measures of segment gross margin and segment operating profit are also before Interest income, Interest expense, Gain (loss) on retirement of long-term obligations, Other income (expense), Net income (loss) attributable to noncontrolling interest, Income (loss) on equity method investments and Income tax benefit (provision). The categories of expenses indicated above, such as depreciation, have been excluded from segment operating performance as they are not considered in the review of information or the evaluation of results by management. There are no significant revenues resulting from transactions between the Company’s operating segments. All intercompany transactions are eliminated to reconcile segment results and assets to the condensed consolidated statements of operations and condensed consolidated balance sheets. Summarized financial information concerning the Company’s reportable segments for the three and nine months ended September 30, 2015 and 2014 is shown in the following tables. The “Other” column (i) represents amounts excluded from specific segments, such as business development operations, stock-based compensation expense and corporate expenses included in Selling, general, administrative and development expense; Other operating expenses; Interest income; Interest expense; Gain (loss) on retirement of long-term obligations; and Other income (expense), and (ii) reconciles segment operating profit to Income from continuing operations before income taxes, as the amounts are not utilized in assessing each segment’s performance. Rental and Management Total Rental and Management Network Development Services Other Total Three Months Ended September 30, 2015 Domestic International (in thousands) Segment revenues $ 807,978 $ 404,871 $ 1,212,849 $ 25,061 $ 1,237,910 Segment operating expenses (1) 187,368 168,318 355,686 9,208 364,894 Interest income, TV Azteca, net — 2,993 2,993 — 2,993 Segment gross margin 620,610 239,546 860,156 15,853 876,009 Segment selling, general, administrative and development expense (1) 31,374 34,737 66,111 3,730 69,841 Segment operating profit $ 589,236 $ 204,809 $ 794,045 $ 12,123 $ 806,168 Stock-based compensation expense $ 18,345 18,345 Other selling, general, administrative and development expense 27,141 27,141 Depreciation, amortization and accretion 341,096 341,096 Other expense (2) 227,611 227,611 Income from continuing operations before income taxes $ 191,975 Total assets $ 19,353,820 $ 7,361,511 $ 26,715,331 $ 70,006 $ 141,451 $ 26,926,788 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $0.5 million and $17.9 million , respectively. (2) Other expense primarily includes interest expense. Rental and Management Total Rental and Management Network Development Services Other Total Three Months Ended September 30, 2014 Domestic International (in thousands) Segment revenues $ 663,570 $ 347,549 $ 1,011,119 $ 27,069 $ 1,038,188 Segment operating expenses (1) 133,951 138,060 272,011 11,746 283,757 Interest income, TV Azteca, net — 2,661 2,661 — 2,661 Segment gross margin 529,619 212,150 741,769 15,323 757,092 Segment selling, general, administrative and development expense (1) 30,955 33,441 64,396 3,020 67,416 Segment operating profit $ 498,664 $ 178,709 $ 677,373 $ 12,303 $ 689,676 Stock-based compensation expense $ 18,269 18,269 Other selling, general, administrative and development expense 23,669 23,669 Depreciation, amortization and accretion 249,066 249,066 Other expense (2) 181,616 181,616 Income from continuing operations before income taxes $ 217,056 Total assets $ 14,202,456 $ 6,190,104 $ 20,392,560 $ 40,903 $ 163,152 $ 20,596,615 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $0.4 million and $17.8 million , respectively. (2) Other expense primarily includes interest expense. Rental and Management Total Rental and Management Network Development Services Other Total Nine Months Ended September 30, 2015 Domestic International (in thousands) Segment revenues $ 2,328,699 $ 1,100,565 $ 3,429,264 $ 62,211 $ 3,491,475 Segment operating expenses (1) 502,572 425,834 928,406 22,527 950,933 Interest income, TV Azteca, net — 8,251 8,251 — 8,251 Segment gross margin 1,826,127 682,982 2,509,109 39,684 2,548,793 Segment selling, general, administrative and development expense (1) 89,439 99,329 188,768 10,605 199,373 Segment operating profit $ 1,736,688 $ 583,653 $ 2,320,341 $ 29,079 $ 2,349,420 Stock-based compensation expense $ 72,251 72,251 Other selling, general, administrative and development expense 84,390 84,390 Depreciation, amortization and accretion 932,972 932,972 Other expense (2) 677,332 677,332 Income from continuing operations before income taxes $ 582,475 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $1.6 million and $70.7 million , respectively. (2) Other expense primarily includes interest expense. Rental and Management Total Rental and Management Network Development Services Other Total Nine Months Ended September 30, 2014 Domestic International (in thousands) Segment revenues $ 1,959,092 $ 1,017,908 $ 2,977,000 $ 76,734 $ 3,053,734 Segment operating expenses (1) 381,800 403,515 785,315 30,529 815,844 Interest income, TV Azteca, net — 7,918 7,918 — 7,918 Segment gross margin 1,577,292 622,311 2,199,603 46,205 2,245,808 Segment selling, general, administrative and development expense (1) 86,677 97,129 183,806 7,876 191,682 Segment operating profit $ 1,490,615 $ 525,182 $ 2,015,797 $ 38,329 $ 2,054,126 Stock-based compensation expense $ 61,708 61,708 Other selling, general, administrative and development expense 65,449 65,449 Depreciation, amortization and accretion 740,256 740,256 Other expense (2) 515,234 515,234 Income from continuing operations before income taxes $ 671,479 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $1.4 million and $60.3 million , respectively. (2) Other expense primarily includes interest expense.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Viom Transaction —On October 21, 2015, the Company, through its wholly owned subsidiary, ATC Asia Pacific Pte. Ltd. (the “Purchaser”), entered into an agreement (the “Share Purchase Agreement”) with Viom Networks Limited (“Viom”), a telecommunications infrastructure company that owns and operates approximately 42,200 wireless communications towers and 200 indoor distributed antenna systems in India, and certain existing Viom shareholders, including the current managing shareholder, SREI Infrastructure Finance Limited, several other minority shareholders and Tata Teleservices Limited (collectively, the “Selling Shareholders”), to acquire a controlling interest of approximately 51% of the outstanding common membership interests of Viom from the Selling Shareholders for cash consideration of approximately 76 billion INR (approximately $1,157 million based on a current estimated rate), subject to certain adjustments (the “Viom Transaction”). Consummation of the Viom Transaction is subject to certain conditions, including regulatory approval. The Viom Transaction is expected to close in mid-2016, and the Company anticipates that it will consolidate the full financial results for Viom. On October 21, 2015, the Purchaser also entered into a shareholders agreement (the “Shareholders Agreement”) with Viom and certain remaining Viom shareholders (collectively, the “Remaining Shareholders”). The Shareholders Agreement will become effective on the closing date of the Viom Transaction. The Shareholders Agreement provides that, among other things, the Remaining Shareholders will have certain governance, anti-dilution and contractual rights. The Remaining Shareholders will have put options and the Purchaser will have a call option pursuant to the time periods and conditions outlined in the Shareholders Agreement. Amendments to Bank Facilities —Effective October 28, 2015, the Company entered into amendment agreements to the 2013 Credit Facility, the 2014 Credit Facility and the Term Loan, which, among other things, (i) extended the maturity dates to June 28, 2019, January 29, 2021 and January 29, 2021, respectively, and (ii) increased the threshold for certain defaults with respect to judgments, attachments or acceleration of indebtedness from $250 million to $300 million . All of the other material terms of the 2013 Credit Facility, the 2014 Credit Facility and Term Loan remain in full force and effect.

Description of Business, Basi27

Description of Business, Basis of Presentation and Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation and Basis of Presentation	The accompanying condensed 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.
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 condensed consolidated financial statements and accompanying notes. Actual results may differ from those estimates, and such differences could be material to the accompanying condensed consolidated financial statements. The significant estimates in the accompanying condensed 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.
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 in GAAP and will become effective for the Company on January 1, 2018. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2016. The standard permits the use of either the retrospective or cumulative effect transition method and leases are not included in the scope of this standard. The Company is evaluating the impact this standard will have on its financial statements. In June 2014, the FASB issued stock-based compensation guidance, which requires a performance target that could be achieved after the requisite service period be treated as a performance condition that affects vesting, rather than a condition that affects the grant-date fair value. The Company early adopted this guidance on a prospective basis during the nine months ended September 30, 2015 , and it did not have a material effect on the Company’s financial statements. In April 2015, the FASB issued new guidance on the presentation of debt issuance costs. The guidance requires debt issuance costs be presented in the balance sheet as a direct deduction from the carrying amount of the related debt liability, consistent with debt discounts and premiums. In August 2015, the FASB clarified that debt issuance costs associated with line of credit arrangements may continue to be presented as an asset, regardless of whether there are any outstanding borrowings on the line of credit arrangement. The update requires retrospective application and the update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2015, with early adoption permitted. The Company does not expect the adoption of this guidance to have a material effect on its financial statements. In September 2015, the FASB issued new guidance on the accounting for measurement-period adjustments. The guidance requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined rather than retrospectively. The effect on earnings as a result of the change to the provisional amounts is calculated as if the accounting had been completed as of the acquisition date. The update requires prospective application and the update is effective for fiscal years, and interim periods within those years, beginning after December 15, 2015, with early adoption permitted. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

Prepaid and Other Current Ass28

Prepaid and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid expense and other current assets	Prepaid and other current assets consisted of the following as of (in thousands): September 30, 2015 December 31, 2014 (1) Prepaid operating ground leases $ 112,965 $ 88,053 Prepaid assets 41,294 23,848 Prepaid income tax 34,332 34,512 Unbilled receivables 31,878 25,352 Value added tax and other consumption tax receivables 20,727 23,228 Other miscellaneous current assets 40,872 69,800 Balance $ 282,068 $ 264,793 (1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill and Other Intangible29

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in the carrying value of goodwill	The changes in the carrying value of goodwill for the Company’s business segments were as follows (in thousands): Rental and Management Network Development Services Total Domestic International Balance as of January 1, 2015 (1) $ 3,356,096 $ 674,090 $ 1,988 $ 4,032,174 Additions 19,677 145,431 — 165,108 Effect of foreign currency translation — (142,111 ) — (142,111 ) Balance as of September 30, 2015 $ 3,375,773 $ 677,410 $ 1,988 $ 4,055,171 (1) January 1, 2015 balances have been revised to reflect purchase accounting measurement period adjustments.
Schedule of finite-lived intangible assets	The Company’s other intangible assets subject to amortization consisted of the following as of (in thousands): September 30, 2015 December 31, 2014 (1) Estimated Useful Lives Gross Carrying Value Accumulated Amortization Net Book Value Gross Carrying Value Accumulated Amortization Net Book Value (years) Acquired network location intangibles (2) Up to 20 $ 3,952,072 $ (1,000,656 ) $ 2,951,416 $ 2,513,788 $ (901,903 ) $ 1,611,885 Acquired customer-related intangibles 15-20 8,606,612 (1,666,473 ) 6,940,139 6,594,469 (1,429,572 ) 5,164,897 Acquired licenses and other intangibles 3-20 28,267 (5,333 ) 22,934 38,443 (3,514 ) 34,929 Economic Rights, TV Azteca 70 22,021 (11,331 ) 10,690 25,522 (12,960 ) 12,562 Total $ 12,608,972 $ (2,683,793 ) $ 9,925,179 $ 9,172,222 $ (2,347,949 ) $ 6,824,273 Deferred financing costs, net (3) N/A 87,218 75,889 Other intangible assets, net $ 10,012,397 $ 6,900,162 (1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments. (2) 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. (3) Deferred financing costs are amortized over the term of the respective debt instruments to which they relate using the effective interest method. This amortization is included in Interest expense rather than in Depreciation, amortization and accretion expense.
Expected future amortization expenses	Based on current exchange rates, the Company expects to record amortization expense (excluding amortization of deferred financing costs) as follows over the remaining current year and the five subsequent years (in millions): Fiscal Year 2015 (remaining year) $ 149.5 2016 594.7 2017 593.2 2018 592.0 2019 589.7 2020 572.0

Accrued Expenses (Tables)

Accrued Expenses (Tables)	9 Months Ended
	Sep. 30, 2015
Accrued Liabilities, Current [Abstract]
Schedule of accrued liabilities	Accrued expenses consisted of the following as of (in thousands): September 30, 2015 December 31, 2014 (1) Acquisition liability (2) $ 300,000 $ — Accrued property and real estate taxes 74,352 61,206 Accrued rent 54,686 34,074 Payroll and related withholdings 50,852 57,110 Accrued construction costs 22,030 46,024 Other accrued expenses 241,336 219,422 Balance $ 743,256 $ 417,836 (1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments. (2) Represents the remaining liability related to the Airtel acquisition on July 1, 2015 (see note 14).

Long-Term Obligations (Tables)

Long-Term Obligations (Tables)	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Schedule of Brazil Credit Facility Sublimits	The Brazil Credit Facility bears interest at a margin over the long-term interest rate, as defined by BNDES (“TJLP”), and the Special Clearance and Escrow System (“SELIC”) as follows (BRL in millions): Maximum Borrowing Amount Contractual Interest Rate Tranche A BRL 34.8 TJLP + 4.25% Tranche B BRL 34.8 SELIC + 4.25% Tranche C BRL 200.0 6.00 % Tranche D BRL 1.4 TJLP
Schedule of Line of Credit Facilities	The key terms under the 2014 Credit Facility, the 2013 Credit Facility and the Term Loan as of September 30, 2015 are as follows ($ in millions): Outstanding Balance Undrawn LOC Maturity Date(1) Current margin over LIBOR (3) Current commitment fee (4) 2014 Credit Facility $ 1,980 $ 7.5 January 31, 2020 (2) 1.250 % 0.150 % 2013 Credit Facility $ 1,080 $ 3.2 June 28, 2018 (2) 1.250 % 0.150 % Term Loan $ 2,000 N/A January 3, 2019 1.250 % N/A (1) In October 2015, the Company entered into amendment agreements, which, among other things, extended the maturity dates for the 2014 Credit Facility, the 2013 Credit Facility and the Term Loan to January 29, 2021, June 28, 2019 and January 29, 2021, respectively (see note 16). (2) Subject to two optional renewal periods. (3) LIBOR means the London Interbank Offered Rate. (4) Fee on undrawn portion of the credit facility.

Derivative Financial Instrume32

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Summary of Derivative Instruments [Abstract]
Schedule of derivative financial instruments	The notional amount and fair value of the interest rate swap agreements were as follows (in thousands): September 30, 2015 December 31, 2014 Local USD Local USD South Africa (Rand) Notional 404,478 29,194 440,614 38,080 Fair Value 3,205 231 1,016 88 Colombia (Colombian Peso) Notional 96,250,000 30,830 100,000,000 41,798 Fair Value 858,788 275 (1,548,688 ) (647 )
Schedule of interest rate swap agreements' impact on other comprehensive income	During the nine months ended September 30, 2015 and 2014 , the interest rate swap agreements and treasury rate lock had the following impact on the Company’s condensed consolidated financial statements (in thousands): Nine Months Ended September 30, Gain(Loss) Recognized in OCI - Effective Portion Gain(Loss) Effective Portion Location of Gain(Loss) Reclassified from AOCI into Income- Effective Portion Gain(Loss) Recognized Location of Gain(Loss) Recognized in Income - Ineffective Portion 2015 $347 $(2,837) Interest Expense/Loss on Retirement of Long-Term Obligations N/A N/A 2014 $(887) $(2,217) Interest Expense N/A N/A During the three months ended September 30, 2015 and 2014 , the interest rate swap agreements had the following impact on the Company’s condensed consolidated financial statements (in thousands): Three Months Ended September 30, Gain(Loss) Recognized in OCI - Effective Portion Gain(Loss) Effective Portion Location of Gain(Loss) Reclassified from AOCI into Income- Effective Portion Gain(Loss) Recognized Location of Gain(Loss) Recognized in Income - Ineffective Portion 2015 $701 $(178) Interest Expense N/A N/A 2014 $(526) $(578) Interest Expense N/A N/A

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of fair value, assets and liabilities measured on recurring basis	The fair value of the Company’s financial assets and liabilities that are required to be measured on a recurring basis at fair value is as follows (in thousands): September 30, 2015 Fair Value Measurements Using Assets/Liabilities at Fair Value Level 1 Level 2 Level 3 Assets: Short-term investments (1) $ 14,485 $ 14,485 Interest rate swap agreements $ 506 $ 506 Embedded derivative in lease agreement $ 14,564 $ 14,564 Liabilities: Acquisition-related contingent consideration $ 18,488 $ 18,488 December 31, 2014 Fair Value Measurements Using Assets/Liabilities at Fair Value Level 1 Level 2 Level 3 Assets: Short-term investments (1) $ 6,302 $ 6,302 Interest rate swap agreements $ 88 $ 88 Liabilities: Acquisition-related contingent consideration $ 28,524 $ 28,524 Interest rate swap agreements $ 647 $ 647 (1) Consists of highly liquid investments with original maturities in excess of three months.
Schedule of business acquisitions by acquisition, contingent consideration	During the three months ended September 30, 2015 and 2014 , the fair value of the contingent consideration changed as follows (in thousands): 2015 2014 Balance as of July 1 $ 24,867 $ 31,025 Additions — 106 Settlements (3,408 ) (209 ) Change in fair value 99 (974 ) Foreign currency translation adjustment (3,070 ) (1,794 ) Other (1) — (730 ) Balance as of September 30 $ 18,488 $ 27,424 During the nine months ended September 30, 2015 and 2014 , the fair value of the contingent consideration changed as follows (in thousands): 2015 2014 Balance as of January 1 $ 28,524 $ 31,890 Additions 1,311 512 Settlements (6,761 ) (1,498 ) Change in fair value 99 (1,344 ) Foreign currency translation adjustment (4,685 ) (1,406 ) Other (1) — (730 ) Balance as of September 30 $ 18,488 $ 27,424 (1) In connection with the sale of operations in Panama in September 2014, the buyer assumed the Company’s potential obligations related to additional purchase price consideration. A summary of the value of the Company’s contingent consideration is as follows (in thousands): Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 Maximum potential value (1) Estimated value at September 30, 2015 (2) Additions (3) Settlements Change in Fair Value Additions (3) Settlements Change in Fair Value Colombia $ 22,642 $ 15,123 $ — $ — $ — $ — $ — $ — Costa Rica — — — (175 ) — — (1,898 ) — Ghana 577 577 — — 99 — — 99 United States 2,788 2,788 — (3,233 ) — 1,311 (4,863 ) — Total $ 26,007 $ 18,488 $ — $ (3,408 ) $ 99 $ 1,311 $ (6,761 ) $ 99 (1) The maximum potential value is based on exchange rates at September 30, 2015 . The minimum value could be zero . (2) Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015 . (3) Based on preliminary acquisition accounting upon closing of certain acquisitions during the three and nine months ended September 30, 2015 .

Accumulated Other Comprehensi34

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of accumulated other comprehensive income (loss)	The changes in Accumulated other comprehensive loss for the three months ended September 30, 2015 and 2014 were as follows (in thousands): Unrealized Losses on Cash Flow Hedges Foreign Total Balance as of July 1, 2015 $ (1,333 ) $ (1,227,188 ) $ (1,228,521 ) Other comprehensive income (loss) before reclassifications, net of tax 717 (605,244 ) (604,527 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 145 — 145 Net current-period other comprehensive income (loss) 862 (605,244 ) (604,382 ) Balance as of September 30, 2015 $ (471 ) $ (1,832,432 ) $ (1,832,903 ) Unrealized Losses on Cash Flow Hedges Deferred Loss on the Settlement of the Treasury Rate Lock Foreign Total Balance as of July 1, 2014 $ (1,301 ) $ (2,630 ) $ (246,989 ) $ (250,920 ) Other comprehensive loss before reclassifications, net of tax (514 ) — (253,424 ) (253,938 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 319 200 — 519 Net current-period other comprehensive (loss) income (195 ) 200 (253,424 ) (253,419 ) Balance as of September 30, 2014 $ (1,496 ) $ (2,430 ) $ (500,413 ) $ (504,339 ) The changes in Accumulated other comprehensive loss for the nine months ended September 30, 2015 and 2014 were as follows (in thousands): Unrealized Losses on Cash Flow Hedges Deferred Loss on the Settlement of the Treasury Rate Lock Foreign Total Balance as of January 1, 2015 $ (1,345 ) $ (2,231 ) $ (790,645 ) $ (794,221 ) Other comprehensive loss before reclassifications, net of tax 377 — (1,041,787 ) (1,041,410 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 497 2,231 — 2,728 Net current-period other comprehensive income (loss) 874 2,231 (1,041,787 ) (1,038,682 ) Balance as of September 30, 2015 $ (471 ) $ — $ (1,832,432 ) $ (1,832,903 ) Unrealized Losses on Cash Flow Hedges Deferred Loss on the Settlement of the Treasury Rate Lock Foreign Total Balance as of January 1, 2014 $ (1,869 ) $ (3,029 ) $ (306,322 ) $ (311,220 ) Other comprehensive loss before reclassifications, net of tax (969 ) — (194,091 ) (195,060 ) Amounts reclassified from accumulated other comprehensive loss, net of tax 1,342 599 — 1,941 Net current-period other comprehensive income (loss) 373 599 (194,091 ) (193,119 ) Balance as of September 30, 2014 $ (1,496 ) $ (2,430 ) $ (500,413 ) $ (504,339 )

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Summary of the company's option activity	The Company’s option activity for the nine months ended September 30, 2015 was as follows: Number of Options Outstanding as of January 1, 2015 6,508,435 Granted 2,004,100 Exercised (441,626 ) Forfeited (105,226 ) Expired (1,475 ) Outstanding as of September 30, 2015 7,964,208
Assumptions used to determine the grant date fair value for options granted	Key assumptions used to apply this pricing model are as follows: Range of risk-free interest rate 1.32%-1.62% Weighted average risk-free interest rate 1.62 % Expected life of option grants 4.5 years Range of expected volatility of underlying stock price 21.09%-21.20% Weighted average expected volatility of underlying stock price 21.09 % Range of expected annual dividend yield 1.50%-1.85%
Summary of the company's restricted stock unit activity	The Company’s RSU and PSU activity for the nine months ended September 30, 2015 was as follows: RSUs PSUs (1) Outstanding as of January 1, 2015 1,758,817 — Granted 692,340 23,379 Vested (688,811 ) — Forfeited (93,746 ) — Outstanding as of September 30, 2015 1,668,600 23,379 (1) Represents the target number of shares issuable at the end of the three -year performance cycle attributable to the first year’s performance period.
Fair value, valuation assumptions	Key assumptions used to apply the Black-Scholes pricing model for shares purchased through the ESPP during the nine months ended September 30, 2015 , which resulted in a fair value per share of $16.40 , were as follows: Approximate risk-free interest rate 0.06 % Expected life of shares 6 months Expected volatility of underlying stock price over the option period 13.91 % Expected annual dividend yield 1.85 %

Equity (Tables)

Equity (Tables)	9 Months Ended
	Sep. 30, 2015
Equity [Abstract]
Schedule of dividends payable	During the nine months ended September 30, 2015 , the Company declared or paid the following cash distributions: Declaration Date Payment Date Record Date Distribution per share Aggregate Payment Amount (in millions) Common Stock December 2, 2014 January 13, 2015 December 16, 2014 $ 0.38 $ 150.7 March 5, 2015 April 28, 2015 April 10, 2015 $ 0.42 $ 177.7 May 21, 2015 July 16, 2015 June 17, 2015 $ 0.44 $ 186.2 September 10, 2015 October 7, 2015 September 23, 2015 $ 0.46 $ 194.8 Series A Preferred Stock December 2, 2014 February 16, 2015 February 1, 2015 $ 1.3125 $ 7.9 April 14, 2015 May 15, 2015 May 1, 2015 $ 1.3125 $ 7.9 July 15, 2015 August 17, 2015 August 1, 2015 $ 1.3125 $ 7.9 Series B Preferred Stock April 14, 2015 May 15, 2015 May 1, 2015 $ 11.1528 $ 15.3 July 15, 2015 August 17, 2015 August 1, 2015 $ 13.7500 $ 18.9

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of earnings per basic and diluted by common class	The following table sets forth basic and diluted net income per common share computational data for the three and nine months ended September 30, 2015 and 2014 (in thousands, except per share data): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Net income attributable to American Tower Corporation stockholders $ 102,999 $ 207,593 $ 452,372 $ 644,523 Dividends on preferred stock (26,781 ) (7,700 ) (63,382 ) (12,075 ) Net income attributable to American Tower Corporation common stockholders 76,218 199,893 388,990 632,448 Basic weighted average common shares outstanding 423,375 396,243 417,280 395,758 Dilutive securities 3,852 4,154 4,072 4,048 Diluted weighted average common shares outstanding 427,227 400,397 421,352 399,806 Basic net income attributable to American Tower Corporation common stockholders per common share $ 0.18 $ 0.50 $ 0.93 $ 1.60 Diluted net income attributable to American Tower Corporation common stockholders per common share $ 0.18 $ 0.50 $ 0.92 $ 1.58
Schedule of antidilutive securities excluded from computation of earnings per share	The following shares were not included in the computation of diluted earnings per share because the effect would be anti-dilutive (in thousands, on a weighted average basis): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Restricted stock awards — — — — Stock options 1,996 1 1,472 2,255 Preferred stock 17,368 6,688 14,724 3,473

Acquisitions and Other Transa38

Acquisitions and Other Transactions (Tables)	9 Months Ended
	Sep. 30, 2015
Business Combination, Description [Abstract]
Schedule of merger and acquisition related costs	During the three and nine months ended September 30, 2015 and 2014 , the Company recorded the following acquisition and merger related expenses and integration costs (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Acquisition and merger related expenses (1) $ 8,587 $ 4,051 $ 16,574 $ 18,657 Integration costs $ 5,938 $ 5,205 $ 12,218 $ 10,891 (1) Acquisition and merger related expenses for the nine months ended September 30, 2015 do not reflect approximately $9.9 million of transaction costs related to the Verizon Transaction as these costs have been capitalized as part of the assets’ fair value.
Schedule of recognized identified assets acquired and liabilities assumed	The following table summarizes the preliminary allocation of the purchase price for the fiscal year 2015 acquisitions based upon their estimated fair value at the date of acquisition (in thousands). Balances are reflected in the accompanying condensed consolidated balance sheet as of September 30, 2015 . Airtel TIM Other International U.S. Current assets $ 15,828 $ — $ — $ 179 Non-current assets 69,224 — 324 — Property and equipment 414,065 259,945 8,762 30,554 Intangible assets (1): Customer-related intangible assets 232,350 361,829 3,537 50,225 Network location intangible assets 309,902 117,084 3,178 31,464 Current liabilities (4,246 ) — — (336 ) Other non-current liabilities (12,507 ) (24,338 ) (333 ) (3,040 ) Net assets acquired 1,024,616 714,520 15,468 109,046 Goodwill (2) 84,035 60,696 700 19,677 Fair value of net assets acquired 1,108,651 775,216 16,168 128,723 Debt assumed — — — — Purchase Price $ 1,108,651 $ 775,216 $ 16,168 $ 128,723 (1) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . (2) Goodwill was allocated to the Company’s rental and management segments. The Company expects goodwill recorded in its domestic rental and management segment will be deductible for tax purposes. The Company expects goodwill recorded in its international rental and management segment will not be deductible for tax purposes, except for in India, where goodwill is expected to be deductible. The following table summarizes the allocation of consideration transferred for the 11,285 communications sites under the Master Prepaid Lease (in thousands). Balances are reflected in the accompanying condensed consolidated balance sheets as of September 30, 2015 and represent the asset balances of the capital lease. Current assets $ 6,079 Non-current assets 144,921 Property and equipment 2,044,900 Intangible assets (1): Customer-related intangible assets 1,856,972 Network location intangible assets 1,172,622 Current liabilities (10,747 ) Other non-current liabilities (2) (250,530 ) Fair value of consideration transferred (3) $ 4,964,217 (1) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . (2) Primarily represents liabilities recorded for asset retirement obligations. (3) Includes approximately $9.9 million of transaction costs, which have been capitalized as part of the assets’ fair value, $5.6 million of which was paid during the nine months ended September 30, 2015 . The following table summarizes the preliminary allocation of the purchase price paid and the amounts of assets acquired and liabilities assumed for the fiscal year 2014 acquisitions based upon their estimated fair value at the date of acquisition (in thousands). Balances are reflected in the consolidated balance sheets in the 2014 Form 10-K. BR Towers Richland Other U.S. Current assets $ 31,832 $ 8,583 $ 797 Non-current assets 9,135 — — Property and equipment 141,422 185,777 38,413 Intangible assets (1): Customer-related intangible assets 495,279 169,452 89,990 Network location intangible assets 136,233 1,700 39,470 Other intangible assets 37,664 — — Current liabilities (23,930 ) (3,635 ) (1,997 ) Other non-current liabilities (101,508 ) (2,922 ) (1,675 ) Net assets acquired 726,127 358,955 164,998 Goodwill (2) 164,955 32,423 15,824 Fair value of net assets acquired 891,082 391,378 180,822 Debt assumed (3) (261,136 ) (201,999 ) — Preferred stock outstanding (61,056 ) — — Purchase Price $ 568,890 $ 189,379 $ 180,822 (1) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . Other intangible assets are amortized on a straight-line basis over the life of the lease, which is a period of 11 years . (2) Goodwill was allocated to the Company’s rental and management segments, and the Company expects goodwill recorded will be deductible for tax purposes except for goodwill associated with BR Towers where goodwill is expected to be partially deductible. (3) Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Richland debt assumed included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million . The fair value adjustments were based primarily on reported market values using Level 2 inputs. The following table summarizes the updated allocation of the purchase price for the fiscal year 2014 acquisitions based upon their estimated fair value at the date of acquisition (in thousands). Balances are reflected in the accompanying condensed consolidated balance sheets herein. BR Towers Richland (1) Other U.S. Current assets $ 31,568 $ 8,583 $ 332 Non-current assets 9,365 — 1,041 Property and equipment 135,916 154,899 38,092 Intangible assets (2): Customer-related intangible assets 495,151 186,455 88,490 Network location intangible assets 135,549 3,409 38,470 Other intangible assets 33,095 — — Current liabilities (24,012 ) (3,635 ) (1,997 ) Other non-current liabilities (101,814 ) (2,922 ) (1,675 ) Net assets acquired 714,818 346,789 162,753 Goodwill (3) 166,097 44,128 18,069 Fair value of net assets acquired 880,915 390,917 180,822 Debt assumed (4) (261,136 ) (201,999 ) — Preferred stock outstanding (61,056 ) — — Purchase Price $ 558,723 $ 188,918 $ 180,822 (1) The allocation of the purchase price was finalized during the nine months ended September 30, 2015 . (2) Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years . Other intangible assets are amortized on a straight-line basis over the life of the lease, which is a period of 11 years . (3) Goodwill was allocated to the Company’s rental and management segments, and the Company expects goodwill recorded will be deductible for tax purposes except for goodwill associated with BR Towers, where goodwill is expected to be partially deductible. (4) Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Assumed Richland debt included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million . The fair value adjustments were based primarily on reported market values using Level 2 inputs.
Schedule of pro forma information	Accordingly, such pro forma amounts are not necessarily indicative of the results that actually would have occurred had the transactions been completed on the dates indicated, nor are they indicative of the future operating results of the Company. Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Pro forma revenues $ 1,243,347 $ 1,262,421 $ 3,749,564 $ 3,739,837 Pro forma net income attributable to American Tower Corporation common stockholders $ 76,489 $ 139,673 $ 356,060 $ 453,520 Pro forma net income per common share amounts: Basic net income attributable to American Tower Corporation common stockholders $ 0.18 $ 0.33 $ 0.84 $ 1.08 Diluted net income attributable to American Tower Corporation common stockholders $ 0.18 $ 0.33 $ 0.83 $ 1.07
Schedule of business acquisitions by acquisition, contingent consideration	During the three months ended September 30, 2015 and 2014 , the fair value of the contingent consideration changed as follows (in thousands): 2015 2014 Balance as of July 1 $ 24,867 $ 31,025 Additions — 106 Settlements (3,408 ) (209 ) Change in fair value 99 (974 ) Foreign currency translation adjustment (3,070 ) (1,794 ) Other (1) — (730 ) Balance as of September 30 $ 18,488 $ 27,424 During the nine months ended September 30, 2015 and 2014 , the fair value of the contingent consideration changed as follows (in thousands): 2015 2014 Balance as of January 1 $ 28,524 $ 31,890 Additions 1,311 512 Settlements (6,761 ) (1,498 ) Change in fair value 99 (1,344 ) Foreign currency translation adjustment (4,685 ) (1,406 ) Other (1) — (730 ) Balance as of September 30 $ 18,488 $ 27,424 (1) In connection with the sale of operations in Panama in September 2014, the buyer assumed the Company’s potential obligations related to additional purchase price consideration. A summary of the value of the Company’s contingent consideration is as follows (in thousands): Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 Maximum potential value (1) Estimated value at September 30, 2015 (2) Additions (3) Settlements Change in Fair Value Additions (3) Settlements Change in Fair Value Colombia $ 22,642 $ 15,123 $ — $ — $ — $ — $ — $ — Costa Rica — — — (175 ) — — (1,898 ) — Ghana 577 577 — — 99 — — 99 United States 2,788 2,788 — (3,233 ) — 1,311 (4,863 ) — Total $ 26,007 $ 18,488 $ — $ (3,408 ) $ 99 $ 1,311 $ (6,761 ) $ 99 (1) The maximum potential value is based on exchange rates at September 30, 2015 . The minimum value could be zero . (2) Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015 . (3) Based on preliminary acquisition accounting upon closing of certain acquisitions during the three and nine months ended September 30, 2015 .

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting, Measurement Disclosures [Abstract]
Summarized financial information concerning the company's reportable segments	Summarized financial information concerning the Company’s reportable segments for the three and nine months ended September 30, 2015 and 2014 is shown in the following tables. The “Other” column (i) represents amounts excluded from specific segments, such as business development operations, stock-based compensation expense and corporate expenses included in Selling, general, administrative and development expense; Other operating expenses; Interest income; Interest expense; Gain (loss) on retirement of long-term obligations; and Other income (expense), and (ii) reconciles segment operating profit to Income from continuing operations before income taxes, as the amounts are not utilized in assessing each segment’s performance. Rental and Management Total Rental and Management Network Development Services Other Total Three Months Ended September 30, 2015 Domestic International (in thousands) Segment revenues $ 807,978 $ 404,871 $ 1,212,849 $ 25,061 $ 1,237,910 Segment operating expenses (1) 187,368 168,318 355,686 9,208 364,894 Interest income, TV Azteca, net — 2,993 2,993 — 2,993 Segment gross margin 620,610 239,546 860,156 15,853 876,009 Segment selling, general, administrative and development expense (1) 31,374 34,737 66,111 3,730 69,841 Segment operating profit $ 589,236 $ 204,809 $ 794,045 $ 12,123 $ 806,168 Stock-based compensation expense $ 18,345 18,345 Other selling, general, administrative and development expense 27,141 27,141 Depreciation, amortization and accretion 341,096 341,096 Other expense (2) 227,611 227,611 Income from continuing operations before income taxes $ 191,975 Total assets $ 19,353,820 $ 7,361,511 $ 26,715,331 $ 70,006 $ 141,451 $ 26,926,788 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $0.5 million and $17.9 million , respectively. (2) Other expense primarily includes interest expense. Rental and Management Total Rental and Management Network Development Services Other Total Three Months Ended September 30, 2014 Domestic International (in thousands) Segment revenues $ 663,570 $ 347,549 $ 1,011,119 $ 27,069 $ 1,038,188 Segment operating expenses (1) 133,951 138,060 272,011 11,746 283,757 Interest income, TV Azteca, net — 2,661 2,661 — 2,661 Segment gross margin 529,619 212,150 741,769 15,323 757,092 Segment selling, general, administrative and development expense (1) 30,955 33,441 64,396 3,020 67,416 Segment operating profit $ 498,664 $ 178,709 $ 677,373 $ 12,303 $ 689,676 Stock-based compensation expense $ 18,269 18,269 Other selling, general, administrative and development expense 23,669 23,669 Depreciation, amortization and accretion 249,066 249,066 Other expense (2) 181,616 181,616 Income from continuing operations before income taxes $ 217,056 Total assets $ 14,202,456 $ 6,190,104 $ 20,392,560 $ 40,903 $ 163,152 $ 20,596,615 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $0.4 million and $17.8 million , respectively. (2) Other expense primarily includes interest expense. Rental and Management Total Rental and Management Network Development Services Other Total Nine Months Ended September 30, 2015 Domestic International (in thousands) Segment revenues $ 2,328,699 $ 1,100,565 $ 3,429,264 $ 62,211 $ 3,491,475 Segment operating expenses (1) 502,572 425,834 928,406 22,527 950,933 Interest income, TV Azteca, net — 8,251 8,251 — 8,251 Segment gross margin 1,826,127 682,982 2,509,109 39,684 2,548,793 Segment selling, general, administrative and development expense (1) 89,439 99,329 188,768 10,605 199,373 Segment operating profit $ 1,736,688 $ 583,653 $ 2,320,341 $ 29,079 $ 2,349,420 Stock-based compensation expense $ 72,251 72,251 Other selling, general, administrative and development expense 84,390 84,390 Depreciation, amortization and accretion 932,972 932,972 Other expense (2) 677,332 677,332 Income from continuing operations before income taxes $ 582,475 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $1.6 million and $70.7 million , respectively. (2) Other expense primarily includes interest expense. Rental and Management Total Rental and Management Network Development Services Other Total Nine Months Ended September 30, 2014 Domestic International (in thousands) Segment revenues $ 1,959,092 $ 1,017,908 $ 2,977,000 $ 76,734 $ 3,053,734 Segment operating expenses (1) 381,800 403,515 785,315 30,529 815,844 Interest income, TV Azteca, net — 7,918 7,918 — 7,918 Segment gross margin 1,577,292 622,311 2,199,603 46,205 2,245,808 Segment selling, general, administrative and development expense (1) 86,677 97,129 183,806 7,876 191,682 Segment operating profit $ 1,490,615 $ 525,182 $ 2,015,797 $ 38,329 $ 2,054,126 Stock-based compensation expense $ 61,708 61,708 Other selling, general, administrative and development expense 65,449 65,449 Depreciation, amortization and accretion 740,256 740,256 Other expense (2) 515,234 515,234 Income from continuing operations before income taxes $ 671,479 (1) Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $1.4 million and $60.3 million , respectively. (2) Other expense primarily includes interest expense.

Description of Business, Basi40

Description of Business, Basis of Presentation and Accounting Policies (Narrative) (Details)	Sep. 30, 2015communications_site	Jul. 01, 2015site	Mar. 27, 2015site
Verizon Transaction
Gain (Loss) on Investments [Line Items]
Number of sites acquired			11,448
Airtel Acquisition
Gain (Loss) on Investments [Line Items]
Number of sites acquired	1	4,699

Prepaid and Other Current Ass41

Prepaid and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	[1]
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid operating ground leases	$ 112,965	$ 88,053
Prepaid assets	41,294	23,848
Prepaid income tax	34,332	34,512
Unbilled receivables	31,878	25,352
Value added tax and other consumption tax receivables	20,727	23,228
Other miscellaneous current assets	40,872	69,800
Balance	$ 282,068	$ 264,793
[1]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments

Goodwill and Other Intangible42

Goodwill and Other Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Indefinite-lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 154.4	$ 103.3	$ 412.5	$ 307.5
Weighted Average
Indefinite-lived Intangible Assets [Line Items]
Remaining amortization period			16 years

Goodwill and Other Intangible43

Goodwill and Other Intangible Assets (Rollforward) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Goodwill [Roll Forward]
Balance as of January 1, 2015	$ 4,032,174	[1]
Additions	165,108
Effect of foreign currency translation	(142,111)
Balance as of September 30, 2015	4,055,171
Rental And Management | Domestic
Goodwill [Roll Forward]
Balance as of January 1, 2015	3,356,096	[1]
Additions	19,677
Effect of foreign currency translation	0
Balance as of September 30, 2015	3,375,773
Rental And Management | International
Goodwill [Roll Forward]
Balance as of January 1, 2015	674,090	[1]
Additions	145,431
Effect of foreign currency translation	(142,111)
Balance as of September 30, 2015	677,410
Network Development Services
Goodwill [Roll Forward]
Balance as of January 1, 2015	1,988	[1]
Additions	0
Effect of foreign currency translation	0
Balance as of September 30, 2015	$ 1,988
[1]	January 1, 2015 balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill and Other Intangible44

Goodwill and Other Intangible Assets (Changes in the Carrying Value of Goodwill) (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2015	Dec. 31, 2014	[1]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value		$ 12,608,972	$ 9,172,222
Accumulated Amortization		(2,683,793)	(2,347,949)
Net Book Value		9,925,179	6,824,273
Deferred financing costs, net	[2]	87,218	75,889
Other intangible assets, net		$ 10,012,397	6,900,162
Estimated useful lives		11 years
Acquired Network Location Intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	[3]	$ 3,952,072	2,513,788
Accumulated Amortization	[3]	(1,000,656)	(901,903)
Net Book Value	[3]	$ 2,951,416	1,611,885
Acquired Network Location Intangibles | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives		20 years
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value		$ 8,606,612	6,594,469
Accumulated Amortization		(1,666,473)	(1,429,572)
Net Book Value		$ 6,940,139	5,164,897
Customer Relationships | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives		15 years
Customer Relationships | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives		20 years
Acquired Licenses And Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value		$ 28,267	38,443
Accumulated Amortization		(5,333)	(3,514)
Net Book Value		$ 22,934	34,929
Acquired Licenses And Other Intangibles | Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives		3 years
Acquired Licenses And Other Intangibles | Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives		20 years
Economic Rights, TV Azteca
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value		$ 22,021	25,522
Accumulated Amortization		(11,331)	(12,960)
Net Book Value		$ 10,690	$ 12,562
Estimated useful lives		70 years
[1]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.
[2]	Deferred financing costs are amortized over the term of the respective debt instruments to which they relate using the effective interest method. This amortization is included in Interest expense rather than in Depreciation, amortization and accretion expense.
[3]	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.

Goodwill and Other Intangible45

Goodwill and Other Intangible Assets (Expected Future Amortization Expenses) (Details) $ in Millions	Sep. 30, 2015USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2015 (remaining year)	$ 149.5
2,016	594.7
2,017	593.2
2,018	592
2,019	589.7
2,020	$ 572

Accrued Expenses (Details)

Accrued Expenses (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014	[2]
Accrued Liabilities, Current [Abstract]
Acquisition liability	[1]	$ 300,000	$ 0
Accrued property and real estate taxes		74,352	61,206
Accrued rent		54,686	34,074
Payroll and related withholdings		50,852	57,110
Accrued construction costs		22,030	46,024
Other accrued expenses		241,336	219,422
Balance		$ 743,256	$ 417,836
[1]	Represents the remaining liability related to the Airtel acquisition on July 1, 2015 (see note 14).
[2]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

Long-Term Obligations (Narrativ

Long-Term Obligations (Narrative) (Details) ₨ in Millions, BRL in Millions, MXN in Billions

Aug. 25, 2015USD ($)

Aug. 25, 2015BRL

May. 18, 2015USD ($)

May. 18, 2015BRL

May. 07, 2015USD ($)

Apr. 29, 2015USD ($)

Feb. 11, 2015USD ($)

May. 31, 2015USD ($)

May. 31, 2015MXN

Sep. 30, 2015USD ($)sitequarter

Sep. 30, 2015INR (₨)

Sep. 30, 2014USD ($)

Sep. 30, 2015USD ($)sitequarterrenewal_period

Sep. 30, 2015BRLrenewal_period

Sep. 30, 2014USD ($)

May. 29, 2015USD ($)

Mar. 30, 2015BRL

Feb. 20, 2015USD ($)

Dec. 31, 2014USD ($)

Dec. 31, 2014BRL

Apr. 30, 2013USD ($)

Debt Instrument [Line Items]

Gain (loss) on retirement of long-term obligations

$ 0

$ (2,969,000)

$ 78,793,000

$ (1,447,000)

Number of annual renewal periods | renewal_period

2

2

Long-term debt, fair value

17,300,000,000

$ 17,300,000,000

$ 15,000,000,000

Proceeds from lines of credit

5,727,831,000

785,000,000

Accrued interest

$ 80,682,000

80,682,000

$ 130,265,000

Loss (gain) on early retirement of long-term obligations

$ 78,793,000

$ (1,447,000)

Indian Facility | Revolving Credit Facility

Debt Instrument [Line Items]

Stated percentage interest rate

10.00%

10.00%

Maximum borrowing capacity

$ 10,000,000

Proceeds from lines of credit

$ 8,100,000

₨ 530

Credit Facility 2014 | Revolving Credit Facility

Debt Instrument [Line Items]

Maximum borrowing capacity

2,000,000,000

$ 2,000,000,000

Proceeds from lines of credit

2,100,000,000

Maximum revolving loan commitments

$ 2,500,000,000

2,500,000,000

Repayments of lines of credit

$ 1,300,000,000

Line of credit facility, optional additional commitments

$ 500,000,000

Credit Facility 2014 | Revolving Credit Facility | Third measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

7

7

Credit Facility 2014 | Revolving Credit Facility | Fourth measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

6

6

Credit Facility 2013 | Revolving Credit Facility

Debt Instrument [Line Items]

Number of annual renewal periods | renewal_period

2

2

Maximum borrowing capacity

$ 2,750,000,000

$ 2,750,000,000

Proceeds from lines of credit

3,600,000,000

Maximum revolving loan commitments

3,500,000,000

Repayments of lines of credit

$ 2,500,000,000

Line of credit facility, optional additional commitments

750,000,000

Revolving Credit Facility | Credit Facility 2013 | Second measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

Revolving Credit Facility | Credit Facility 2013 | Third measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

7

7

Revolving Credit Facility | Credit Facility 2013 | Fourth measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

6

6

Secured Debt | Series 2015-1 Class A

Debt Instrument [Line Items]

Long-term Debt

$ 350,000,000

Secured Debt | Series 2015-2 Class A

Debt Instrument [Line Items]

Long-term Debt

$ 525,000,000

Secured Debt | Commercial Mortgage Pass Through Certificates Series 2015

Debt Instrument [Line Items]

Cash trap debt service credit ratio

1.30

1.30

Number of consecutive quarters required for release of funds | quarter

2

2

Minimum debt service credit ratio

1.15

1.15

Restricted cash and cash equivalents

$ 16,000,000

$ 16,000,000

Secured Debt | GTP Notes

Debt Instrument [Line Items]

Number of broadcast and wireless communications towers | site

3,621

3,621

Unsecured Debt | Mexican loan

Debt Instrument [Line Items]

Bridge loan | MXN

MXN 5.2

Repayments of unsecured debt

$ 251,200,000

MXN 3.9

Unsecured Debt | BR Towers Credit Facility

Debt Instrument [Line Items]

Long-term debt, fair value | BRL

BRL 48.1

Unsecured Debt | Brazil Credit Facility

Debt Instrument [Line Items]

Maximum borrowing capacity | BRL

BRL 271

Proceeds from lines of credit

$ 2,500,000

BRL 9.1

$ 13,300,000

BRL 40

$ 12,500,000

BRL 49.8

Long-term debt, weighted average interest rate

11.20%

11.20%

Unsecured Debt | Term Loan 2013

Debt Instrument [Line Items]

Number of annual renewal periods | renewal_period

2

2

Term Loan, optional additional commitments

$ 500,000,000

Maximum incremental term loan commitment

$ 2,500,000,000

$ 2,500,000,000

Unsecured Debt | Term Loan 2013 | Second measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

7.25

7.25

Unsecured Debt | Term Loan 2013 | Third measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

7

7

Unsecured Debt | Term Loan 2013 | Fourth measurement period

Debt Instrument [Line Items]

Ratio of total debt to EBITDA

6

6

Senior Notes

Debt Instrument [Line Items]

Maximum Adjusted EBITDA

3.5

3.5

Senior Notes | Series 2015-1 Class A

Debt Instrument [Line Items]

Stated percentage interest rate

2.35%

Senior Notes | Series 2015-2 Class A

Debt Instrument [Line Items]

Stated percentage interest rate

3.482%

Senior Notes | Commercial Mortgage Pass Through Certificates Series 2015

Debt Instrument [Line Items]

Gain (loss) on retirement of long-term obligations

$ 800,000

Senior Notes | Four Point Six Two Five Percent Senior Notes

Debt Instrument [Line Items]

Debt Instrument, Redemption Price, Percentage

100.5898%

Repayments of Senior Debt

$ 613,600,000

Accrued interest

10,000,000

Senior Notes | Seven Point Zero Zero Percent Senior Notes

Debt Instrument [Line Items]

Gain (loss) on retirement of long-term obligations

$ 74,300,000

Stated percentage interest rate

7.00%

7.00%

7.00%

Debt Instrument, Redemption Price, Percentage

114.0629%

Repayments of Senior Debt

$ 571,700,000

Accrued interest

$ 1,400,000

Senior Notes | Two Point Eight Zero Percent Senior Notes

Debt Instrument [Line Items]

Stated percentage interest rate

2.80%

Debt Instrument, Redemption Price, Percentage

100.00%

100.00%

Long-term Debt, Gross

$ 750,000,000

Proceeds from Issuance of Debt

$ 1,480,100,000

Repurchase Price As Percentage Of Principal

101.00%

101.00%

Senior Notes | Four Point Zero Zero Percent Senior Notes

Debt Instrument [Line Items]

Stated percentage interest rate

4.00%

Debt Instrument, Redemption Price, Percentage

100.00%

100.00%

Long-term Debt, Gross

$ 750,000,000

Repurchase Price As Percentage Of Principal

101.00%

101.00%

Senior Notes | Four Point Six Two Five Percent Senior Notes

Debt Instrument [Line Items]

Stated percentage interest rate

4.625%

Loss (gain) on early retirement of long-term obligations

$ 3,700,000

Long-Term Obligations (Schedule

Long-Term Obligations (Schedule of Brazil Credit Facility Sublimits) (Details) BRL in Millions	9 Months Ended
	Sep. 30, 2015BRL
Brazil Credit Facility Tranche A
Line of Credit Facility [Line Items]
Maximum borrowing capacity	BRL 34.8
Basis spread on variable rate	4.25%
Brazil Credit Facility Tranche B
Line of Credit Facility [Line Items]
Maximum borrowing capacity	BRL 34.8
Basis spread on variable rate	4.25%
Brazil Credit Facility Tranche C
Line of Credit Facility [Line Items]
Stated percentage interest rate	6.00%
Maximum borrowing capacity	BRL 200
Brazil Credit Facility Tranche D
Line of Credit Facility [Line Items]
Maximum borrowing capacity	BRL 1.4

Long-Term Obligations (Schedu49

Long-Term Obligations (Schedule of Line of Credit Facilities) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)renewal_period
Line of Credit Facility [Line Items]
Number of annual renewal periods | renewal_period	2
Credit Facility 2014 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit outstanding balance	$ 1,980
Letters of credit, undrawn amount	$ 7.5
Commitment fee percentage	0.15%	[1]
Credit Facility 2014 | London Interbank Offered Rate (LIBOR) | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%	[2]
Credit Facility 2013 | Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit outstanding balance	$ 1,080
Letters of credit, undrawn amount	$ 3.2
Commitment fee percentage	0.15%	[1]
Number of annual renewal periods | renewal_period	2
Credit Facility 2013 | London Interbank Offered Rate (LIBOR) | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%	[2]
Term Loan 2013 | Unsecured Debt
Line of Credit Facility [Line Items]
Line of credit outstanding balance	$ 2,000
Number of annual renewal periods | renewal_period	2
Term Loan 2013 | London Interbank Offered Rate (LIBOR) | Unsecured Debt
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%	[2]
[1]	Fee on undrawn portion of the credit facility.
[2]	LIBOR means the London Interbank Offered Rate.

Derivative Financial Instrume50

Derivative Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Jul. 01, 2015	Apr. 29, 2015
Derivative [Line Items]
Embedded derivative, fair value of asset		$ 14.6
Designated as Hedging Instrument
Derivative [Line Items]
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	$ 0.1
Seven Point Zero Zero Percent Senior Notes
Derivative [Line Items]
Reclassification adjustment from AOCI on deferred loss	$ 2
Seven Point Zero Zero Percent Senior Notes | Senior Notes
Derivative [Line Items]
Stated percentage interest rate	7.00%		7.00%

Derivative Financial Instrume51

Derivative Financial Instruments (Schedule of Interest Rate Swap Agreements) (Details) - Interest Rate Swap ZAR in Thousands, COP in Thousands, $ in Thousands	Sep. 30, 2015COP	Sep. 30, 2015USD ($)	Sep. 30, 2015ZAR	Dec. 31, 2014COP	Dec. 31, 2014USD ($)	Dec. 31, 2014ZAR
South African Facility
Derivative [Line Items]
Notional		$ 29,194	ZAR 404,478		$ 38,080	ZAR 440,614
Derivative, fair value, net		231	ZAR 3,205		88	ZAR 1,016
2014 Colombian Long Term Credit Facility
Derivative [Line Items]
Notional	COP 96,250,000	30,830		COP 100,000,000	41,798
Derivative, fair value, net	COP (858,788)	$ (275)		COP 1,548,688	$ 647

Derivative Financial Instrume52

Derivative Financial Instruments (Schedule of Interest Rate Swap Agreements Impact on Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest rate swaps and treasury locks
Derivative [Line Items]
Gain (Loss) Recognized in OCI - Effective Portion	$ 701	$ (526)	$ 347	$ (887)
Interest rate swaps and treasury locks
Derivative [Line Items]
Gain (Loss) Reclassified from AOCI into Income - Effective Portion	$ (178)	$ (578)	$ (2,837)	$ (2,217)

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)		9 Months Ended
		Sep. 30, 2014	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration arrangements, low range of outcomes			$ 0
Contingent consideration arrangements, high range of outcomes	[1]		26,007,000
Carrying value of long-term obligations, including current portion			17,000,000,000	$ 14,600,000,000
Long-term debt, fair value			17,300,000,000	15,000,000,000
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value			9,900,000,000	9,700,000,000
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value			$ 7,400,000,000	$ 5,300,000,000
Operations In Panama and Portion of Engineering Business
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal group, including discontinued operation, consideration		$ 17,900,000
Disposal group, including discontinued operation, property, plant and equipment, noncurrent		8,100,000
Disposal group, including discontinued operation, intangible assets, noncurrent		7,800,000
Disposal group, including discontinued operation, goodwill, noncurrent		3,600,000
Goodwill and intangible asset impairment		$ 2,200,000
[1]	The maximum potential value is based on exchange rates at September 30, 2015. The minimum value could be zero.

Fair Value Measurements (Assets

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands		Sep. 30, 2015		Jul. 01, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments		$ 14,485				$ 6,302
Embedded derivative, fair value of asset				$ 14,600
Acquisition-related contingent consideration		18,488	[1]		$ 24,867	28,524	$ 27,424	$ 31,025	$ 31,890
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	[2]	14,485				6,302
Embedded derivative, fair value of asset		14,564
Acquisition-related contingent consideration		18,488				28,524
Fair Value, Measurements, Recurring | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements		506				88
Interest rate swap agreements						647
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	[2]	14,485				6,302
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2 | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate swap agreements		506				88
Interest rate swap agreements						647
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Embedded derivative, fair value of asset		14,564
Acquisition-related contingent consideration		$ 18,488				$ 28,524
[1]	Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015.
[2]	Consists of highly liquid investments with original maturities in excess of three months.

Fair Value Measurement (Conting

Fair Value Measurement (Contingent Consideration Change) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period		$ 24,867		$ 31,025	$ 28,524		$ 31,890
Additions		0		106	1,311		512
Settlements		(3,408)		(209)	(6,761)		(1,498)
Change in fair value		99		(974)	99		(1,344)
Foreign currency translation adjustment		(3,070)		(1,794)	(4,685)		(1,406)
Other	[1]	0		(730)	0		(730)
Balance at End of Period		$ 18,488	[2]	$ 27,424	$ 18,488	[2]	$ 27,424
[1]	In connection with the sale of operations in Panama in September 2014, the buyer assumed the Company’s potential obligations related to additional purchase price consideration.
[2]	Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015.

Accumulated Other Comprehensi56

Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Apr. 29, 2015
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ (1,228,521)	$ (250,920)	$ (794,221)	$ (311,220)
Other comprehensive income (loss) before reclassifications, net of tax	(604,527)	(253,938)	(1,041,410)	(195,060)
Amounts reclassified from accumulated other comprehensive loss, net of tax	145	519	2,728	1,941
Net current-period other comprehensive income (loss)	(604,382)	(253,419)	(1,038,682)	(193,119)
Balance at end of period	(1,832,903)	(504,339)	(1,832,903)	(504,339)
Reclassification of unrealized losses on cash flow hedges to net income, tax	$ 20	36	66	132
Seven Point Zero Zero Percent Senior Notes
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Reclassification adjustment from AOCI on deferred loss			$ 2,000
Seven Point Zero Zero Percent Senior Notes | Senior Notes
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Stated percentage interest rate	7.00%		7.00%		7.00%
Unrealized Losses on Cash Flow Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ (1,333)	(1,301)	$ (1,345)	(1,869)
Other comprehensive income (loss) before reclassifications, net of tax	717	(514)	377	(969)
Amounts reclassified from accumulated other comprehensive loss, net of tax	145	319	497	1,342
Net current-period other comprehensive income (loss)	862	(195)	874	373
Balance at end of period	(471)	(1,496)	(471)	(1,496)
Reclassification of unrealized losses on cash flow hedges to net income, tax	100	100	100	100
Treasury Lock
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period		(2,630)	(2,231)	(3,029)
Other comprehensive income (loss) before reclassifications, net of tax		0	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax		200	2,231	599
Net current-period other comprehensive income (loss)		200	2,231	599
Balance at end of period	0	(2,430)	0	(2,430)
Foreign Currency Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(1,227,188)	(246,989)	(790,645)	(306,322)
Other comprehensive income (loss) before reclassifications, net of tax	(605,244)	(253,424)	(1,041,787)	(194,091)
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0	0	0
Net current-period other comprehensive income (loss)	(605,244)	(253,424)	(1,041,787)	(194,091)
Balance at end of period	$ (1,832,432)	$ (500,413)	$ (1,832,432)	$ (500,413)

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Tax Expense (Benefit), Continuing Operations [Abstract]
REIT liquidation tax charge	$ 93,000,000		$ 93,000,000
REIT liquidiation deferred tax benefit	5,400,000		5,400,000
Unrecognized tax benefits that would impact effective tax rate	26,500,000		26,500,000		$ 31,900,000
Impact of change in unrecognized tax benefit, lower	0		0
Impact of change in unrecognized tax benefits, upper	5,100,000		5,100,000
Penalties and tax-related interest expense during period	700,000	$ 1,800,000	2,300,000	$ 4,800,000
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	3,100,000	$ 1,400,000	3,100,000	$ 1,400,000
Unrecognized tax benefits, income tax penalties and interest accrued	$ 19,400,000		$ 19,400,000		$ 24,900,000

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 18,345	$ 18,269	$ 72,251	$ 61,708
Capitalized stock-based compensation expense		$ 500	$ 400	$ 1,600	$ 1,200
2007 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				4 years
Expiration period				10 years
Number of shares issuable under stock incentive plan		11,700,000		11,700,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 800		$ 1,500
Total unrecognized compensation expense		1,300		$ 1,300
Total compensation cost not yet recognized, period for recognition				1 year
Three year performance grant, shares granted				70,135
Shares granted, grant date fair value not yet established	[1]			46,756
Weighted average grant date fair value				$ 94.57
Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of potential target shares				0.00%
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of potential target shares				200.00%
Performance Shares | 2007 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				3 years
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value (in dollars per share)				$ 15.09
Total unrecognized compensation expense		33,700		$ 33,700
Total compensation cost not yet recognized, period for recognition				2 years
Restricted stock awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense		$ 87,400		$ 87,400
Total compensation cost not yet recognized, period for recognition				2 years
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Eligible employee discount, stock purchase plan				15.00%
Issuance of common stock - stock purchase plan (in shares)				66,000
ESPP, purchase price per share		$ 16.40		$ 16.40
[1]	Represents the target number of shares issuable at the end of the three-year performance cycle attributable to the first year’s performance period.

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of the Company's Option Activity) (Details) - Employee Stock Option	9 Months Ended
	Sep. 30, 2015shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at Beginning of Period	6,508,435
Granted	2,004,100
Exercised	(441,626)
Forfeited	(105,226)
Expired	(1,475)
Outstanding at End of Period	7,964,208

Stock-Based Compensation (Assum

Stock-Based Compensation (Assumptions Used to Determine the Grant Date Fair Value for Options Granted) (Details) - Employee Stock Option	9 Months Ended
	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum range of risk-free interest rate	1.32%
Maximum range of risk-free interest rate	1.62%
Approximate risk-free interest rate	1.62%
Expected life of shares	4 years 4 months 52 days
Minimum range of expected volatility of underlying stock price	21.09%
Maximum range of expected volatility of underlying stock price	21.20%
Expected volatility of underlying stock price over the option period	21.09%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected annual dividend yield	1.50%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected annual dividend yield	1.85%

Stock-Based Compensation (Sum61

Stock-Based Compensation (Summary of the Company's Restricted Stock Unit Activity) (Details)	9 Months Ended
	Sep. 30, 2015shares
Restricted Stock Units
Restricted Stock Unit Activity, Outstanding [Roll Forward]
Outstanding at Beginning of Period	1,758,817
Granted	692,340
Vested	(688,811)
Forfeited	(93,746)
Outstanding at End of Period	1,668,600
Performance Shares
Restricted Stock Unit Activity, Outstanding [Roll Forward]
Outstanding at Beginning of Period	0	[1]
Granted	23,379	[1]
Vested	0	[1]
Forfeited	0	[1]
Outstanding at End of Period	23,379	[1]
2007 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
2007 Plan | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
[1]	Represents the target number of shares issuable at the end of the three-year performance cycle attributable to the first year’s performance period.

Stock-Based Compensation Schedu

Stock-Based Compensation Schedule of employee stock purchase plan valuation assumptions (Details) - Employee Stock	9 Months Ended
	Sep. 30, 2015
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Approximate risk-free interest rate	0.06%
Expected life of shares	6 months
Expected volatility of underlying stock price over the option period	13.91%
Expected annual dividend yield	1.85%

Equity (Narrative) (Details)

Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Mar. 05, 2015	Mar. 03, 2015
Class of Stock [Line Items]
Common stock, shares issued	426,307,336		399,508,751
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Proceeds from issuance of common stock	$ 2,440,327	$ 0
Issuance of preferred stock	1,337,946	583,105
Proceeds from stock options and stock purchase plan	29,324	$ 47,938
Accrued dividend, restricted stock units	4,300
Paid dividend, restricted stock units	1,200
Common Stock
Class of Stock [Line Items]
Common stock, shares issued					23,500,000
Common stock, par value (in dollars per share)					$ 0.01
Shares issued, price per share					97
Additional stock issued in conjunction with over-allotment				2,350,000
Proceeds from issuance of common stock	$ 2,440,000
Series B Preferred Stock
Class of Stock [Line Items]
Shares issued, price per share					$ 100
Preferred stock, shares issued	1,375,000				12,500,000
Preferred stock, dividend rate percentage	5.50%
Preferred stock, par value (in dollars per share)	$ 0.01				$ 0.01
Additional shares issued in conjunction with over-allotment - preferred				1,250,000
Issuance of preferred stock	$ 1,340,000
Liquidation preference per share	$ 1,000
Liquidation preference, depositary shares	100
Depositary shares, percentage of preferred shares					0.1
Series B Preferred Stock | Minimum
Class of Stock [Line Items]
Automatic conversion factor	8.5911
Series B Preferred Stock | Maximum
Class of Stock [Line Items]
Automatic conversion factor	10.3093
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued	6,000,000		6,000,000
Preferred stock, dividend rate percentage	5.25%		5.25%
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Liquidation preference per share	$ 100
Series A Preferred Stock | Minimum
Class of Stock [Line Items]
Automatic conversion factor	0.9174
Series A Preferred Stock | Maximum
Class of Stock [Line Items]
Automatic conversion factor	1.1468

Equity (Schedule Of Dividends)

Equity (Schedule Of Dividends) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Dividends Payable [Line Items]
Distribution per share, declared - common stock	$ 0.46	$ 0.36	$ 1.32	$ 1.02
Aggregate payment amount - common stock			$ 516,012	$ 261,913
Aggregate payment amount - preferred stock			57,866	$ 8,138
Common Stock | Fourth Quarter
Dividends Payable [Line Items]
Aggregate payment amount - common stock			$ 194,800
Common Stock | First Quarter
Dividends Payable [Line Items]
Distribution per share, paid - common stock			$ 0.38
Aggregate payment amount - common stock			$ 150,700
Common Stock | Second Quarter
Dividends Payable [Line Items]
Distribution per share, paid - common stock			$ 0.42
Aggregate payment amount - common stock			$ 177,700
Common Stock | Third Quarter
Dividends Payable [Line Items]
Distribution per share, paid - common stock			$ 0.44
Distribution per share, declared - common stock			$ 0.46
Aggregate payment amount - common stock			$ 186,200
Series A Preferred Stock | First Quarter
Dividends Payable [Line Items]
Distributions per share, paid - preferred stock			$ 1.3125
Aggregate payment amount - preferred stock			$ 7,900
Series A Preferred Stock | Second Quarter
Dividends Payable [Line Items]
Distributions per share, paid - preferred stock			$ 1.3125
Aggregate payment amount - preferred stock			$ 7,900
Series A Preferred Stock | Third Quarter
Dividends Payable [Line Items]
Distributions per share, paid - preferred stock			$ 1.3125
Aggregate payment amount - preferred stock			$ 7,900
Series B Preferred Stock | Second Quarter
Dividends Payable [Line Items]
Distributions per share, paid - preferred stock			$ 11.1528
Aggregate payment amount - preferred stock			$ 15,300
Series B Preferred Stock | Third Quarter
Dividends Payable [Line Items]
Distributions per share, paid - preferred stock			$ 13.75
Aggregate payment amount - preferred stock			$ 18,900

Earnings Per Share (Schedule of

Earnings Per Share (Schedule of Earnings Per Basic And Diluted by Common Class) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income attributable to American Tower Corporation stockholders	$ 102,999	$ 207,593	$ 452,372	$ 644,523
Dividends on preferred stock	(26,781)	(7,700)	(63,382)	(12,075)
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION COMMON STOCKHOLDERS	$ 76,218	$ 199,893	$ 388,990	$ 632,448
Basic weighted average common shares outstanding (in shares)	423,375	396,243	417,280	395,758
Dilutive securities (in shares)	3,852	4,154	4,072	4,048
Diluted weighted average common shares outstanding (in shares)	427,227	400,397	421,352	399,806
Basic net income attributable to American Tower Corporation common stockholders per common share (in dollars per share)	$ 0.18	$ 0.50	$ 0.93	$ 1.60
Diluted net income attributable to American Tower Corporation common stockholders per common share (in dollars per share)	$ 0.18	$ 0.50	$ 0.92	$ 1.58

Earnings Per Share (Shares Excl

Earnings Per Share (Shares Excluded From Dilutive Effect) (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	0	0
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,996	1	1,472	2,255
Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	17,368	6,688	14,724	3,473

Commitments And Contingencies (

Commitments And Contingencies (Narrative) (Details) ₨ in Billions	Mar. 27, 2015USD ($)communications_sitesiterenewal_period	Jan. 21, 2014USD ($)	Jan. 21, 2014INR (₨)	Dec. 31, 2000USD ($)tower	Sep. 30, 2015USD ($)towerrenewal_periodshares
Long-term Purchase Commitment [Line Items]
India tax assessment		$ 369,000,000	₨ 22.6
Verizon Transaction
Long-term Purchase Commitment [Line Items]
Number of sites acquired | site	11,448
Verizon Transaction | Leased Sites
Long-term Purchase Commitment [Line Items]
Initial lease term	10 years
Number of units leased | communications_site	11,285
Right to lease, weighted average term	28 years
Successive terms to renew lease | renewal_period	8
Operating lease, renewal term	5 years
Verizon Transaction
Long-term Purchase Commitment [Line Items]
Estimated future minimum rental receipts	$ 3,000,000,000
Operating lease, future minimum rental receipts, average recognition period	10 years
Estimated future minimum rental payments	$ 2,200,000,000
Operating lease, future minimum rental payments, average recognition period	17 years
Number of units leased | communications_site	11,285
Right to lease, weighted average term	28 years
Aggregate purchase option price for towers	$ 5,000,000,000
Customer lease, initial term	10 years
Successive terms to renew lease | renewal_period	8
Operating lease, renewal term	5 years
At T Transaction
Long-term Purchase Commitment [Line Items]
Number of sites acquired | tower					31
Number of units leased | tower					2,400
Aggregate purchase option price for towers					$ 691,700,000
Successive terms to renew lease | renewal_period					4
Lessee leasing arrangements, operating leases, term of contract					27 years
Purchase price accretion rate (per year)					10.00%
At T Transaction | Commitments prior to June 30, 2020
Long-term Purchase Commitment [Line Items]
Operating lease, renewal term					5 years
At T Transaction | Commitments subsequent to June 30, 2020
Long-term Purchase Commitment [Line Items]
Operating lease, renewal term					1 year
ALLTEL Transaction
Long-term Purchase Commitment [Line Items]
Number of units leased | tower				1,800
Aggregate purchase option price for towers					$ 74,700,000
Purchase price accretion rate (per year)				3.00%
Long-term purchase commitment, time period				15 years
Cash purchase price per tower				$ 27,500
Purchase price of tower in shares of common stock | shares					769
Value of potential shares payable					$ 119,800,000

Acquisitions and Other Transa68

Acquisitions and Other Transactions (Narrative) (Details) BRL in Millions		Sep. 30, 2015USD ($)property_interestcommunications_site		Sep. 30, 2015BRL	Jul. 01, 2015USD ($)site	Apr. 29, 2015USD ($)communications_site	Apr. 29, 2015BRLcommunications_site	Mar. 27, 2015USD ($)communications_sitesiterenewal_period	Nov. 19, 2014USD ($)property_interesttower	Apr. 03, 2014USD ($)property_interestcommunications_site	Sep. 30, 2015USD ($)property_interestcommunications_site		Sep. 30, 2015USD ($)property_interestcommunications_site		Dec. 31, 2014USD ($)property_interestcommunications_site		Sep. 30, 2015BRLproperty_interestcommunications_site	Jun. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Dec. 31, 2013USD ($)
Business Acquisition [Line Items]
Pro forma information, revenue of acquiree since acquisition date, actual											$ 172,800,000		$ 289,100,000
Pro forma information gross margin of acquiree since acquisition date actual											76,800,000		$ 132,900,000
Estimated useful lives													11 years
Acquisition-related contingent consideration		$ 18,488,000	[1]								18,488,000	[1]	$ 18,488,000	[1]	$ 28,524,000			$ 24,867,000	$ 27,424,000	$ 31,025,000	$ 31,890,000
Value added tax and other consumption tax receivables		20,727,000									20,727,000		20,727,000		23,228,000	[2]
Contingent consideration arrangements, low range of outcomes		0									0		$ 0
Customer Relationships | Maximum
Business Acquisition [Line Items]
Estimated useful lives													20 years
Customer Relationships | Maximum | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Estimated useful lives													20 years
Acquired Network Location | Maximum
Business Acquisition [Line Items]
Estimated useful lives													20 years
Acquired Network Location | Maximum | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Estimated useful lives													20 years
Verizon Transaction
Business Acquisition [Line Items]
Number of sites acquired | site								11,448
Aggregate purchase price								$ 5,053,000,000
Transaction costs		9,900,000						9,900,000			9,900,000		$ 9,900,000
Transaction costs paid		$ 5,600,000									$ 5,600,000		$ 5,600,000
Verizon Transaction | Leased Sites
Business Acquisition [Line Items]
Aggregate purchase price								$ 4,964,000,000
Number of units leased | communications_site								11,285
Right to lease, weighted average term								28 years
Initial lease term								10 years
Successive terms to renew lease | renewal_period								8
Operating lease, renewal term								5 years
Future monthly sublease rent per tower								$ 1,900
Fixed annual rent escalation percentage								2.00%
Verizon Transaction | Owned Sites
Business Acquisition [Line Items]
Number of sites acquired | communications_site		163						163			163		163				163
Aggregate purchase price								$ 99,000,000
TIM Acquisition
Business Acquisition [Line Items]
Number of sites acquired | communications_site		1,125				4,176	4,176				1,125		1,125				1,125
Aggregate purchase price		$ 130,900,000		BRL 516.9		$ 644,300,000	BRL 1,900
Letters of credit, undrawn amount		$ 12,000,000									$ 12,000,000		$ 12,000,000				BRL 47.8
TIM Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													775,216,000
Assumption of existing indebtedness at historical cost													$ 0
Other International Acquisitions 2015
Business Acquisition [Line Items]
Number of sites acquired | communications_site		399									399		399				399
Aggregate purchase price													$ 16,200,000
Other International Acquisitions 2015 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													16,168,000
Assumption of existing indebtedness at historical cost													$ 0
Other Us Acquisition 2015
Business Acquisition [Line Items]
Number of sites acquired | communications_site		199									199		199				199
Aggregate purchase price													$ 128,700,000
Number of property interests acquired | property_interest		3									3		3				3
Acquisition-related contingent consideration		$ 1,300,000									$ 1,300,000		$ 1,300,000
Other Us Acquisition 2015 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													128,723,000
Assumption of existing indebtedness at historical cost													0
BR Towers
Business Acquisition [Line Items]
Number of sites acquired | tower									2,504
Aggregate purchase price									$ 568,900,000				558,700,000
Letters of credit, undrawn amount		$ 82,600,000									$ 82,600,000		82,600,000
Number of property interests acquired | property_interest									4
Additional sites to be acquired | tower									2,113
Right to use, property interests acquired | property_interest									43
Payments for repurchase of trust preferred securities									$ 61,100,000
Assumption of existing indebtedness at historical cost									261,100,000
Value of liabilities assumed									$ 11,500,000
BR Towers | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price															568,890,000
Assumption of existing indebtedness at historical cost	[3]														261,136,000
Richland Acquisition
Business Acquisition [Line Items]
Number of sites acquired | communications_site										59
Aggregate purchase price										$ 189,400,000			$ 188,900,000
Number of property interests acquired | property_interest										4
Assumption of existing indebtedness at historical cost										$ 196,500,000
Liabilities, fair value adjustment										$ 5,500,000
Richland Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price															189,379,000
Assumption of existing indebtedness at historical cost	[3]														$ 201,999,000
Other International Acquisitions 2014
Business Acquisition [Line Items]
Number of sites acquired | communications_site															159
Aggregate purchase price															$ 28,300,000
Value added tax and other consumption tax receivables															$ 1,200,000
Other International Acquisitions 2014 | Mexico
Business Acquisition [Line Items]
Number of sites acquired | communications_site															299
Aggregate purchase price															$ 40,300,000
Assumption of existing indebtedness at historical cost															3,400,000
Value added tax and other consumption tax receivables															5,600,000
Consideration transferred, other															36,300,000
Partial cash consideration transferred															$ 4,000,000
Other US Acquisition 2014
Business Acquisition [Line Items]
Number of sites acquired | communications_site															184
Aggregate purchase price															$ 180,800,000
Number of property interests acquired | property_interest															6
Acquisition-related contingent consideration															$ 6,300,000
Other US Acquisition 2014 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price															180,822,000
Assumption of existing indebtedness at historical cost	[3]														$ 0
Airtel Acquisition
Business Acquisition [Line Items]
Number of sites acquired		1			4,699						1		1				1
Aggregate purchase price					$ 1,109,000,000
Payments to acquire business											$ 806,500,000
Airtel Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Aggregate purchase price													$ 1,108,651,000
Assumption of existing indebtedness at historical cost													$ 0
[1]	Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015.
[2]	December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments
[3]	Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Assumed Richland debt included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million. The fair value adjustments were based primarily on reported market values using Level 2 inputs.

Acquisitions and Other Transa69

Acquisitions and Other Transactions (Schedule of merger and acquisition related costs) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Business Combination, Description [Abstract]
Acquisition and merger related expenses	[1]	$ 8,587	$ 4,051	$ 16,574	$ 18,657
Integration costs		$ 5,938	$ 5,205	$ 12,218	$ 10,891
[1]	Acquisition and merger related expenses for the nine months ended September 30, 2015 do not reflect approximately $9.9 million of transaction costs related to the Verizon Transaction as these costs have been capitalized as part of the assets’ fair value.

Acquisitions and Other Transa70

Acquisitions and Other Transactions (Schedule of recognized identified assets acquired and liabilities assumed) (Details) $ in Thousands, BRL in Millions		Sep. 30, 2015USD ($)	Sep. 30, 2015BRL	Jul. 01, 2015USD ($)	Apr. 29, 2015USD ($)	Apr. 29, 2015BRL	Mar. 27, 2015USD ($)	Nov. 19, 2014USD ($)	Apr. 03, 2014USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Intangible assets:
Goodwill		$ 4,055,171								$ 4,055,171	$ 4,032,174	[1]
Verizon Transaction
Intangible assets:
Aggregate purchase price							$ 5,053,000
Airtel Acquisition
Intangible assets:
Aggregate purchase price				$ 1,109,000
Airtel Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		15,828								15,828
Non-current assets		69,224								69,224
Property and equipment		414,065								414,065
Intangible assets:
Customer-related intangible assets	[2]	232,350								232,350
Network location intangible assets	[2]	309,902								309,902
Current liabilities		(4,246)								(4,246)
Other non-current liabilities		(12,507)								(12,507)
Net assets acquired		1,024,616								1,024,616
Goodwill	[3]	84,035								84,035
Fair value of net assets acquired		1,108,651								1,108,651
Debt assumed										0
Aggregate purchase price										1,108,651
TIM Acquisition
Intangible assets:
Aggregate purchase price		130,900	BRL 516.9		$ 644,300	BRL 1,900
TIM Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		0								0
Non-current assets		0								0
Property and equipment		259,945								259,945
Intangible assets:
Customer-related intangible assets	[2]	361,829								361,829
Network location intangible assets	[2]	117,084								117,084
Current liabilities		0								0
Other non-current liabilities		(24,338)								(24,338)
Net assets acquired		714,520								714,520
Goodwill	[3]	60,696								60,696
Fair value of net assets acquired		775,216								775,216
Debt assumed										0
Aggregate purchase price										775,216
Other International Acquisitions 2015
Intangible assets:
Aggregate purchase price										16,200
Other International Acquisitions 2015 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		0								0
Non-current assets		324								324
Property and equipment		8,762								8,762
Intangible assets:
Customer-related intangible assets	[2]	3,537								3,537
Network location intangible assets	[2]	3,178								3,178
Current liabilities		0								0
Other non-current liabilities		(333)								(333)
Net assets acquired		15,468								15,468
Goodwill	[3]	700								700
Fair value of net assets acquired		16,168								16,168
Debt assumed										0
Aggregate purchase price										16,168
Other Us Acquisition 2015
Intangible assets:
Aggregate purchase price										128,700
Other Us Acquisition 2015 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		179								179
Non-current assets		0								0
Property and equipment		30,554								30,554
Intangible assets:
Customer-related intangible assets	[2]	50,225								50,225
Network location intangible assets	[2]	31,464								31,464
Current liabilities		(336)								(336)
Other non-current liabilities		(3,040)								(3,040)
Net assets acquired		109,046								109,046
Goodwill	[3]	19,677								19,677
Fair value of net assets acquired		128,723								128,723
Debt assumed										0
Aggregate purchase price										128,723
BR Towers
Intangible assets:
Debt assumed								$ (261,100)
Aggregate purchase price								$ 568,900		558,700
BR Towers | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets											31,832
Non-current assets											9,135
Property and equipment											141,422
Intangible assets:
Customer-related intangible assets	[4]										495,279
Current liabilities											(23,930)
Other non-current liabilities											(101,508)
Net assets acquired											726,127
Goodwill	[5]										164,955
Fair value of net assets acquired											891,082
Debt assumed	[6]										(261,136)
Preferred stock outstanding											(61,056)
Aggregate purchase price											568,890
BR Towers | Preliminary Purchase Price Allocation | Acquired Network Location
Intangible assets:
Network location intangible assets	[4]										136,233
Other Intangible Assets, Net	[4]										37,664
BR Towers | Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		31,568								31,568
Non-current assets		9,365								9,365
Property and equipment		135,916								135,916
Intangible assets:
Customer-related intangible assets	[4]	495,151								495,151
Current liabilities		(24,012)								(24,012)
Other non-current liabilities		(101,814)								(101,814)
Net assets acquired		714,818								714,818
Goodwill	[5]	166,097								166,097
Fair value of net assets acquired		880,915								880,915
Debt assumed	[6]									(261,136)
Preferred stock outstanding		(61,056)								(61,056)
Aggregate purchase price										558,723
BR Towers | Purchase Price Allocation | Acquired Network Location
Intangible assets:
Network location intangible assets	[4]	135,549								135,549
Other Intangible Assets, Net	[4]	33,095								33,095
Richland Acquisition
Intangible assets:
Debt assumed									$ (196,500)
Aggregate purchase price									$ 189,400	188,900
Richland Acquisition | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets											8,583
Non-current assets											0
Property and equipment											185,777
Intangible assets:
Customer-related intangible assets	[4]										169,452
Current liabilities											(3,635)
Other non-current liabilities											(2,922)
Net assets acquired											358,955
Goodwill	[5]										32,423
Fair value of net assets acquired											391,378
Debt assumed	[6]										(201,999)
Preferred stock outstanding											0
Aggregate purchase price											189,379
Richland Acquisition | Preliminary Purchase Price Allocation | Acquired Network Location
Intangible assets:
Network location intangible assets	[4]										1,700
Other Intangible Assets, Net	[4]										0
Richland Acquisition | Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	[7]	8,583								8,583
Non-current assets	[7]	0								0
Property and equipment	[7]	154,899								154,899
Intangible assets:
Customer-related intangible assets	[4],[7]	186,455								186,455
Current liabilities	[7]	(3,635)								(3,635)
Other non-current liabilities	[7]	(2,922)								(2,922)
Net assets acquired	[7]	346,789								346,789
Goodwill	[7]	44,128								44,128
Fair value of net assets acquired	[7]	390,917								390,917
Debt assumed	[7]									(201,999)
Preferred stock outstanding		0								0
Aggregate purchase price	[7]									188,918
Richland Acquisition | Purchase Price Allocation | Acquired Network Location
Intangible assets:
Network location intangible assets	[4],[7]	3,409								3,409
Other Intangible Assets, Net	[4],[7]	0								0
Other US Acquisition 2014
Intangible assets:
Aggregate purchase price											180,800
Other US Acquisition 2014 | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets											797
Non-current assets											0
Property and equipment											38,413
Intangible assets:
Customer-related intangible assets	[4]										89,990
Current liabilities											(1,997)
Other non-current liabilities											(1,675)
Net assets acquired											164,998
Goodwill	[5]										15,824
Fair value of net assets acquired											180,822
Debt assumed	[6]										0
Preferred stock outstanding											0
Aggregate purchase price											180,822
Other US Acquisition 2014 | Preliminary Purchase Price Allocation | Acquired Network Location
Intangible assets:
Network location intangible assets	[4]										39,470
Other Intangible Assets, Net	[4]										$ 0
Other US Acquisition 2014 | Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		332								332
Non-current assets		1,041								1,041
Property and equipment		38,092								38,092
Intangible assets:
Customer-related intangible assets	[4]	88,490								88,490
Current liabilities		(1,997)								(1,997)
Other non-current liabilities		(1,675)								(1,675)
Net assets acquired		162,753								162,753
Goodwill	[5]	18,069								18,069
Fair value of net assets acquired		180,822								180,822
Debt assumed	[6]									0
Preferred stock outstanding		0								0
Aggregate purchase price										180,822
Other US Acquisition 2014 | Purchase Price Allocation | Acquired Network Location
Intangible assets:
Network location intangible assets	[4]	38,470								38,470
Other Intangible Assets, Net	[4]	0								0
Leased Sites | Verizon Transaction
Intangible assets:
Aggregate purchase price							$ 4,964,000
Leased Sites | Verizon Transaction | Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets		6,079								6,079
Non-current assets		144,921								144,921
Property and equipment		2,044,900								2,044,900
Intangible assets:
Customer-related intangible assets	[2]	1,856,972								1,856,972
Network location intangible assets	[2]	1,172,622								1,172,622
Current liabilities		(10,747)								(10,747)
Other non-current liabilities	[8]	(250,530)								(250,530)
Fair value of net assets acquired	[9]	$ 4,964,217								$ 4,964,217
[1]	January 1, 2015 balances have been revised to reflect purchase accounting measurement period adjustments.
[2]	Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years.
[3]	Goodwill was allocated to the Company’s rental and management segments. The Company expects goodwill recorded in its domestic rental and management segment will be deductible for tax purposes. The Company expects goodwill recorded in its international rental and management segment will not be deductible for tax purposes, except for in India, where goodwill is expected to be deductible.
[4]	Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years. Other intangible assets are amortized on a straight-line basis over the life of the lease, which is a period of 11 years.
[5]	Goodwill was allocated to the Company’s rental and management segments, and the Company expects goodwill recorded will be deductible for tax purposes except for goodwill associated with BR Towers, where goodwill is expected to be partially deductible.
[6]	Assumed BR Towers debt approximated fair value at the date of acquisition and included $11.5 million of current indebtedness. Assumed Richland debt included $196.5 million of Richland’s indebtedness and a fair value adjustment of $5.5 million. The fair value adjustments were based primarily on reported market values using Level 2 inputs.
[7]	The allocation of the purchase price was finalized during the nine months ended September 30, 2015.
[8]	Primarily represents liabilities recorded for asset retirement obligations.
[9]	Includes approximately $9.9 million of transaction costs, which have been capitalized as part of the assets’ fair value, $5.6 million of which was paid during the nine months ended September 30, 2015.

Acquisitions and Other Transa71

Acquisitions and Other Transactions (Business Acquisition, Pro Forma Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Business Acquisition, Pro Forma Information [Abstract]
Pro forma revenues	$ 1,243,347	$ 1,262,421	$ 3,749,564	$ 3,739,837
Pro forma net income attributable to American Tower Corporation common stockholders	$ 76,489	$ 139,673	$ 356,060	$ 453,520
Basic net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 0.18	$ 0.33	$ 0.84	$ 1.08
Diluted net income attributable to American Tower Corporation common stockholders (in dollars per share)	$ 0.18	$ 0.33	$ 0.83	$ 1.07

Acquisitions and Other Transa72

Acquisitions and Other Transactions (Schedule of business acquisitions by acquisitions, contingent consideration) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	[1]	$ 26,007			$ 26,007
Acquisition-related contingent consideration		18,488	[2]	$ 27,424	18,488	[2]	$ 27,424	$ 24,867	$ 28,524	$ 31,025	$ 31,890
Asset additions during period	[3]	0			1,311
Settlements		(3,408)			(6,761)
Change in fair value		99		$ (974)	99		$ (1,344)
COLOMBIA
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	[1]	22,642			22,642
Acquisition-related contingent consideration	[2]	15,123			15,123
Asset additions during period	[3]	0			0
Settlements		0			0
Change in fair value		0			0
COSTA RICA
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	[1]	0			0
Acquisition-related contingent consideration	[2]	0			0
Asset additions during period	[3]	0			0
Settlements		(175)			(1,898)
Change in fair value		0			0
GHANA
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	[1]	577			577
Acquisition-related contingent consideration	[2]	577			577
Asset additions during period	[3]	0			0
Settlements		0			0
Change in fair value		99			99
UNITED STATES
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	[1]	2,788			2,788
Acquisition-related contingent consideration	[2]	2,788			2,788
Asset additions during period	[3]	0			1,311
Settlements		(3,233)			(4,863)
Change in fair value		$ 0			$ 0
[1]	The maximum potential value is based on exchange rates at September 30, 2015. The minimum value could be zero.
[2]	Estimate is determined using a probability weighted average of expected outcomes as of September 30, 2015.
[3]	Based on preliminary acquisition accounting upon closing of certain acquisitions during the three and nine months ended September 30, 2015.

Business Segments (Narrative) (

Business Segments (Narrative) (Details)	9 Months Ended
	Sep. 30, 2015segment
Segment Reporting, Measurement Disclosures [Abstract]
Number of reportable segments	3

Business Segments (Summarized F

Business Segments (Summarized Financial Information Concerning the Company's Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014		Sep. 30, 2015		Sep. 30, 2014		Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment revenues	$ 1,237,910		$ 1,038,188		$ 3,491,475		$ 3,053,734
Segment operating expenses	364,894	[1]	283,757	[2]	950,933	[3]	815,844	[4]
Segment gross margin	876,009		757,092		2,548,793		2,245,808
Segment selling, general, administrative and development expense	69,841	[1]	67,416	[2]	199,373	[3]	191,682	[4]
Segment operating profit	806,168		689,676		2,349,420		2,054,126
Stock-based compensation expense	18,345		18,269		72,251		61,708
Other selling, general, administrative and development expense	27,141		23,669		84,390		65,449
Depreciation, amortization and accretion	341,096		249,066		932,972		740,256
Other expense	227,611	[5]	181,616	[6]	677,332	[5]	515,234	[6]
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	191,975		217,056		582,475		671,479
Total assets	26,926,788		20,596,615		26,926,788		20,596,615		$ 21,331,932
Selling General Administrative And Development Expense
Segment Reporting Information [Line Items]
Stock-based compensation expense	17,850		17,824		70,697		60,306
TV Azteca
Segment Reporting Information [Line Items]
Interest income, TV Azteca, net	2,993		2,661		8,251		7,918
Operating Segments | Rental And Management
Segment Reporting Information [Line Items]
Segment revenues	1,212,849		1,011,119		3,429,264		2,977,000
Segment operating expenses	355,686	[1]	272,011	[2]	928,406	[3]	785,315	[4]
Segment gross margin	860,156		741,769		2,509,109		2,199,603
Segment selling, general, administrative and development expense	66,111	[1]	64,396	[2]	188,768	[3]	183,806	[4]
Segment operating profit	794,045		677,373		2,320,341		2,015,797
Total assets	26,715,331		20,392,560		26,715,331		20,392,560
Operating Segments | Rental And Management | TV Azteca
Segment Reporting Information [Line Items]
Interest income, TV Azteca, net	2,993		2,661		8,251		7,918
Operating Segments | Rental And Management | Domestic
Segment Reporting Information [Line Items]
Segment revenues	807,978		663,570		2,328,699		1,959,092
Segment operating expenses	187,368	[1]	133,951	[2]	502,572	[3]	381,800	[4]
Segment gross margin	620,610		529,619		1,826,127		1,577,292
Segment selling, general, administrative and development expense	31,374	[1]	30,955	[2]	89,439	[3]	86,677	[4]
Segment operating profit	589,236		498,664		1,736,688		1,490,615
Total assets	19,353,820		14,202,456		19,353,820		14,202,456
Operating Segments | Rental And Management | International
Segment Reporting Information [Line Items]
Segment revenues	404,871		347,549		1,100,565		1,017,908
Segment operating expenses	168,318	[1]	138,060	[2]	425,834	[3]	403,515	[4]
Segment gross margin	239,546		212,150		682,982		622,311
Segment selling, general, administrative and development expense	34,737	[1]	33,441	[2]	99,329	[3]	97,129	[4]
Segment operating profit	204,809		178,709		583,653		525,182
Total assets	7,361,511		6,190,104		7,361,511		6,190,104
Operating Segments | Rental And Management | International | TV Azteca
Segment Reporting Information [Line Items]
Interest income, TV Azteca, net	2,993		2,661		8,251		7,918
Operating Segments | Network Development Services
Segment Reporting Information [Line Items]
Segment revenues	25,061		27,069		62,211		76,734
Segment operating expenses	9,208	[1]	11,746	[2]	22,527	[3]	30,529	[4]
Segment gross margin	15,853		15,323		39,684		46,205
Segment selling, general, administrative and development expense	3,730	[1]	3,020	[2]	10,605	[3]	7,876	[4]
Segment operating profit	12,123		12,303		29,079		38,329
Total assets	70,006		40,903		70,006		40,903
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Stock-based compensation expense	18,345		18,269		72,251		61,708
Other selling, general, administrative and development expense	27,141		23,669		84,390		65,449
Depreciation, amortization and accretion	341,096		249,066		932,972		740,256
Other expense	227,611	[5]	181,616	[6]	677,332	[5]	515,234	[6]
Total assets	141,451		163,152		141,451		163,152
Corporate, Non-Segment | Operating Expense
Segment Reporting Information [Line Items]
Stock-based compensation expense	500		400		1,600		1,400
Corporate, Non-Segment | Selling General Administrative And Development Expense
Segment Reporting Information [Line Items]
Stock-based compensation expense	$ 17,900		$ 17,800		$ 70,700		$ 60,300
[1]	Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $0.5 million and $17.9 million, respectively.
[2]	Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $0.4 million and $17.8 million, respectively.
[3]	Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $1.6 million and $70.7 million, respectively.
[4]	Segment operating expenses and segment selling, general, administrative and development expense exclude stock-based compensation expense of $1.4 million and $60.3 million, respectively.
[5]	Other expense primarily includes interest expense.
[6]	Other expense primarily includes interest expense.

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) ₨ in Billions	Oct. 21, 2015USD ($)sitesystem	Oct. 21, 2015INR (₨)sitesystem	Oct. 28, 2015USD ($)	Sep. 30, 2015USD ($)
Credit Facility 2013 | Revolving Credit Facility
Subsequent Event [Line Items]
Debt covenant, threshold on indebtedness				$ 250,000,000
Credit Facility 2014 | Revolving Credit Facility
Subsequent Event [Line Items]
Debt covenant, threshold on indebtedness				250,000,000
Term Loan 2013 | Unsecured Debt
Subsequent Event [Line Items]
Debt covenant, threshold on indebtedness				$ 250,000,000
Subsequent Event | Viom Transaction
Subsequent Event [Line Items]
Number of sites acquired | site	42,200	42,200
Distributed antenna systems acquired | system	200	200
Percentage of voting interests acquired	51.00%	51.00%
Aggregate purchase price	$ 1,157,000,000	₨ 76
Subsequent Event | Credit Facility 2013 | Revolving Credit Facility
Subsequent Event [Line Items]
Debt covenant, threshold on indebtedness			$ 300,000,000
Subsequent Event | Credit Facility 2014 | Revolving Credit Facility
Subsequent Event [Line Items]
Debt covenant, threshold on indebtedness			300,000,000
Subsequent Event | Term Loan 2013 | Unsecured Debt
Subsequent Event [Line Items]
Debt covenant, threshold on indebtedness			$ 300,000,000