American Tower (AMT) 10-Q30 Apr 152015 Q1 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
Document and Entity Information	Mar. 31, 2015	Apr. 22, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Entity Registrant Name	AMERICAN TOWER CORP /MA/
Entity Central Index Key	1053507
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		423,089,008

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS-Unaudited (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$323,400	$313,492
Restricted cash	129,505	160,206
Short-term investments	14,394	6,302
Accounts receivable, net	175,784	199,074
Prepaid and other current assets	269,181	255,083	[1]
Deferred income taxes	13,555	14,510
Total current assets	925,819	948,667
PROPERTY AND EQUIPMENT, net	9,422,641	7,595,939
GOODWILL	3,980,174	4,028,549	[2]
OTHER INTANGIBLE ASSETS, net	9,536,782	6,908,043	[3]
DEFERRED INCOME TAXES	226,710	253,186
DEFERRED RENT ASSET	1,059,953	1,030,707
NOTES RECEIVABLE AND OTHER NON-CURRENT ASSETS	778,115	566,454
TOTAL	25,930,194	21,331,545
CURRENT LIABILITIES:
Accounts payable	72,512	90,366
Accrued expenses	392,450	417,754
Distributions payable	179,192	159,864
Accrued interest	77,654	130,265
Current portion of long-term obligations	789,152	897,624
Unearned revenue	220,454	233,819
Total current liabilities	1,731,414	1,929,692
LONG-TERM OBLIGATIONS	14,930,952	13,711,084
ASSET RETIREMENT OBLIGATIONS	792,991	609,035
OTHER NON-CURRENT LIABILITIES	1,043,198	1,028,382
Total liabilities	18,498,555	17,278,193
COMMITMENTS AND CONTINGENCIES
EQUITY:
Common stock: $.01 par value; 1,000,000,000 shares authorized; 425,883,631 and 399,508,751 shares issued; and 423,073,605 and 396,698,725 shares outstanding, respectively	4,259	3,995
Additional paid-in capital	9,583,498	5,788,786
Distributions in excess of earnings	-822,545	-837,320
Accumulated other comprehensive loss	-1,205,860	-794,221
Treasury stock (2,810,026 shares at cost)	-207,740	-207,740
Total American Tower Corporation equity	7,351,686	3,953,560
Noncontrolling interest	79,953	99,792
Total equity	7,431,639	4,053,352
TOTAL	25,930,194	21,331,545
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 20,000,000 shares authorized; 5.50%, Series B, 1,375,000 and no shares issued and outstanding, respectively	60	60
Total equity	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 20,000,000 shares authorized; 5.50%, Series B, 1,375,000 and no shares issued and outstanding, respectively	14	0
Total equity	$14

[1]	DecemberÂ 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.
[2]	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.

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS-Unaudited (Parenthetical) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 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	425,883,631	399,508,751
Common stock, shares outstanding	423,073,605	396,698,725
Treasury stock, shares	2,810,026	2,810,026
Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$0.01	0.01
Preferred stock, shares authorized	20,000,000	20,000,000
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$0.01
Preferred stock, shares issued	6,000,000	6,000,000
Preferred stock, shares outstanding	6,000,000	6,000,000
Preferred Stock, Dividend Rate, Percentage	5.25%	5.25%
Series B Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued	1,375,000	0
Preferred stock, shares outstanding	1,375,000	0
Preferred Stock, Dividend Rate, Percentage	5.50%	5.50%

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS-Unaudited (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
REVENUES:
Rental and management	$1,062,180	$960,120
Network development services	17,010	23,969
Total operating revenues	1,079,190	984,089
OPERATING EXPENSES:
Rental and management (including stock-based compensation expense of $432 and $372, respectively)	259,257	250,835
Network development services (including stock-based compensation expense of $139 and $132, respectively)	5,383	9,934
Depreciation, amortization and accretion	263,520	245,763
Selling, general, administrative and development expense (including stock-based compensation expense of $29,290 and $24,100, respectively)	123,290	110,029
Other operating expenses	7,774	13,891
Total operating expenses	659,224	630,452
OPERATING INCOME	419,966	353,637
OTHER INCOME (EXPENSE):
Interest income, TV Azteca, net of interest expense of $370 and $371, respectively	2,596	2,595
Interest expense	-147,934	-143,307
Loss on retirement of long-term obligations	-3,725	-238
Other expense (including unrealized foreign currency losses of $55,468 and $2,005, respectively)	-54,503	-3,743
Total other expense	-200,602	-142,675
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	219,364	210,962
Income tax provision	-23,872	-17,649
NET INCOME	195,492	193,313
Net (income) loss attributable to noncontrolling interest	-2,175	9,186
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION STOCKHOLDERS	193,317	202,499
Dividends on preferred stock	-9,819	0
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION COMMON STOCKHOLDERS	183,498	202,499
NET INCOME PER COMMON SHARE AMOUNTS:
Basic net income attributable to American Tower Corporation common stockholders (in dollars per share)	$0.45	$0.51
Diluted net income attributable to American Tower Corporation common stockholders (in dollars per share)	$0.45	$0.51
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
Basic (in shares)	405,111	395,146
Diluted (in shares)	409,399	399,120
DISTRIBUTIONS DECLARED PER COMMON SHARE	$0.42	$0.32
Excluding TV Azteca
OTHER INCOME (EXPENSE):
Interest income	$2,964	$2,018

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS-Unaudited (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Stock-based compensation expense	$29,861	$24,604
Interest income (net of interest expense), TV Azteca	147,934	143,307
Rental And Management
Stock-based compensation expense	432	372
Network Development Services
Stock-based compensation expense	139	132
Selling General Administrative And Development Expense
Stock-based compensation expense	29,290	24,100
Other Expense
Unrealized foreign currency losses	55,468	2,005
TV Azteca
Interest income (net of interest expense), TV Azteca	$370	$371

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE (LOSS) INCOME -Unaudited (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$195,492	$193,313
Other comprehensive (loss) income:
Changes in fair value of cash flow hedges, net of taxes of $51 and $117, respectively	-942	-704
Reclassification of unrealized losses on cash flow hedges to net income, net of taxes of $24 and $55, respectively	387	914
Foreign currency translation adjustments, net of taxes of $12,609 and $1,056, respectively	-432,961	22,492
Other comprehensive (loss) income	-433,516	22,702
Comprehensive (loss) income	-238,024	216,015
Comprehensive loss attributable to noncontrolling interest	19,702	25,294
Comprehensive (loss) income attributable to American Tower Corporation stockholders	($218,322)	$241,309

CONDENSED_CONSOLIDATED_STATEME3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME-Unaudited (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net change in fair value of cash flow hedges, tax	($51)	$117
Reclassification of unrealized losses on cash flow hedges to net income, tax	24	55
Foreign currency translation adjustments, tax	($12,609)	$1,056

CONDENSED_CONSOLIDATED_STATEME4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS-Unaudited (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS PROVIDED BY OPERATING ACTIVITIES:
Net income	$195,492	$193,313
Adjustments to reconcile net income to cash provided by operating activities:
Stock-based compensation expense	29,861	24,604
Depreciation, amortization and accretion	263,520	245,763
Loss on early retirement of long-term obligations	3,725	238
Other non-cash items reflected in statements of operations	66,309	5,060
Increase in net deferred rent asset	-25,074	-21,393
Decrease (increase) in restricted cash	28,180	-8,347
Increase in assets	-2,779	-43,449
(Decrease) increase in liabilities	-49,304	80,793
Cash provided by operating activities	509,930	476,582
CASH FLOWS FROM INVESTING ACTIVITIES:
Payments for purchase of property and equipment and construction activities	-159,184	-213,891
Payments for acquisitions, net of cash acquired	-20,946	-62,761
Payment for Verizon transaction	-5,058,019	0
Proceeds from sale of short-term investments and other non-current assets	72,684	138,228
Payments for short-term investments	-82,557	-151,263
Deposits, restricted cash and other	-1,397	-1,369
Cash used for investing activities	-5,249,419	-291,056
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayments of short-term borrowings, net	0	-172
Borrowings under credit facilities	3,150,000	0
Proceeds from issuance of senior notes, net	0	769,640
Proceeds from term loan	500,000	0
Proceeds from other long-term borrowings	0	3,033
Repayments of notes payable, credit facilities, senior notes and capital leases	-2,490,771	-916,632
Distributions to noncontrolling interest holders, net	-137	-154
Proceeds from stock options	5,106	13,795
Proceeds from the issuance of common stock, net	2,440,390	0
Proceeds from the issuance of preferred stock, net	1,338,009	0
Deferred financing costs and other financing activities	-22,558	-21,857
Distributions paid on common stock	-152,037	-554
Distributions paid on preferred stock	-7,875	0
Cash provided by (used for) financing activities	4,760,127	-152,901
Net effect of changes in foreign currency exchange rates on cash and cash equivalents	-10,730	7,238
NET INCREASE IN CASH AND CASH EQUIVALENTS	9,908	39,863
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	313,492	293,576
CASH AND CASH EQUIVALENTS, END OF PERIOD	323,400	333,439
CASH PAID FOR INCOME TAXES (NET OF REFUNDS OF $922 AND $738, RESPECTIVELY)	14,714	19,094
CASH PAID FOR INTEREST	199,022	154,497
NON-CASH INVESTING AND FINANCING ACTIVITIES:
(DECREASE) INCREASE IN ACCOUNTS PAYABLE AND ACCRUED EXPENSES FOR PURCHASES OF PROPERTY AND EQUIPMENT AND CONSTRUCTION ACTIVITIES	-26,499	7,809
PURCHASES OF PROPERTY AND EQUIPMENT UNDER CAPITAL LEASES	$4,394	$6,301

CONDENSED_CONSOLIDATED_STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS-Unaudited (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Cash Flows [Abstract]
Proceeds from income tax refunds	$922	$738

CONDENSED_CONSOLIDATED_STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY-Unaudited (USD $)	Total	Series A Preferred Stock	Series B Preferred Stock	Common Stock	Treasury Stock	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Preferred Stock	Accumulated Other Comprehensive Loss	Distributions in Excess of Earnings	Noncontrolling Interest
In Thousands, except Share data, unless otherwise specified	Total	Series A Preferred Stock	Series B Preferred Stock	Common Stock	Treasury Stock	Additional Paid-in Capital	Series A Preferred Stock	Series B Preferred Stock	Series B Preferred Stock	Accumulated Other Comprehensive Loss	Distributions in Excess of Earnings	Noncontrolling Interest
BEGINNING BALANCE at Dec. 31, 2013	$3,590,040			$3,976	($207,740)	$5,130,616				($311,220)	($1,081,467)	$55,875
BEGINNING BALANCE (shares) at Dec. 31, 2013				397,674,350	-2,810,026
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity (shares)				795,919
Stock-based compensation related activity	22,794			8		22,786
Changes in fair value of cash flow hedges, net of tax	-704									-780		76
Reclassification of unrealized losses on cash flow hedges to net income, net of tax	914									879		35
Foreign currency translation adjustment, net of tax	22,492									38,711		-16,219
Distributions to noncontrolling interest	-154											-154
Common stock dividends/distributions declared	-127,090										-127,090
Net income (loss)	193,313										202,499	-9,186
ENDING BALANCE at Mar. 31, 2014	3,701,605			3,984	-207,740	5,153,402				-272,410	-1,006,058	30,427
ENDING BALANCE (shares) at Mar. 31, 2014				398,470,269	-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	0
BEGINNING BALANCE (shares) at Dec. 31, 2014	396,698,725			399,508,751	-2,810,026
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related activity (shares)				524,880
Stock-based compensation related activity	16,591			5		16,586
Issuance of common stock, (shares)				25,850,000
Issuance of common stock	2,440,390			259			2,440,131
Issuance of preferred stock, (shares)									1,375,000
Issuance of preferred stock	1,338,009							1,337,995	14
Changes in fair value of cash flow hedges, net of tax	-942									-909		-33
Reclassification of unrealized losses on cash flow hedges to net income, net of tax	387									372		15
Foreign currency translation adjustment, net of tax	-432,961									-411,102		-21,859
Distributions to noncontrolling interest	-137											-137
Common stock dividends/distributions declared	-178,542										-178,542
Net income (loss)	195,492										193,317	2,175
ENDING BALANCE at Mar. 31, 2015	$7,431,639	$60	$14	$4,259	($207,740)	$9,583,498				($1,205,860)	($822,545)	$79,953
Preferred Stock Ending Balance (shares) at Mar. 31, 2015		6,000,000	1,375,000
ENDING BALANCE (shares) at Mar. 31, 2015	423,073,605			425,883,631	-2,810,026

Description_of_Business_Basis_

Description of Business, Basis of Presentation and Accounting Policies	3 Months Ended
	Mar. 31, 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 on its income and gains that it distributes to its stockholders, 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 March 31, 2015, the Company’s QRSs included its domestic tower leasing business, most of its operations in Costa Rica, Germany and Mexico and a portion 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”).

	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 the Company’s 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.

	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 on January 1, 2018. 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 during the three months ended March 31, 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. The update requires retrospective application and the update is effective for annual reporting periods beginning after December 15, 2015. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

Prepaid_and_Other_Current_Asse

Prepaid and Other Current Assets	3 Months Ended
	Mar. 31, 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):



		31-Mar-15		December 31, 2014 (1)
	Prepaid operating ground leases	$	94,254	$	88,508

	Prepaid income tax	39,022		34,512

	Prepaid assets	33,919		23,848

	Unbilled receivables	26,763		25,352

	Value added tax and other consumption tax receivables	21,920		23,228

	Other miscellaneous current assets	53,303		59,635

	Balance	$	269,181	$	255,083

	(1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	3 Months Ended
Goodwill and Other Intangible Assets	Mar. 31, 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			Total
			Rental and Management							Development
			Domestic			International				Services
	Balance as of January 1, 2015 (1)		$	3,353,851		$	672,710			$	1,988		$	4,028,549
	Balance as of January 1, 2015 (1)		$	3,353,851		$	672,710			$	1,988		$	4,028,549
	Additions		9,548			—				—			9,548
	Additions		9,548			—				—			9,548
	Effect of foreign currency translation		—			(57,923		)		—			(57,923		)
	Effect of foreign currency translation		—			(57,923		)		—			(57,923		)
	Balance as of March 31, 2015		$	3,363,399		$	614,787			$	1,988		$	3,980,174
	Balance as of March 31, 2015		$	3,363,399		$	614,787			$	1,988		$	3,980,174

	-1	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):



					31-Mar-15											December 31, 2014 (1)
			Estimated		Gross				Accumulated			Net Book				Gross		Accumulated			Net Book
			Useful		Carrying				Amortization			Value				Carrying		Amortization			Value
			Lives		Value											Value
			(years)
	Acquired network location intangibles (2)		Up to 20		$	3,654,516			$	(924,264	)	$	2,730,252			$	2,515,472	$	(901,903	)	$	1,613,569
	Acquired network location intangibles (2)		Up to 20		$	3,654,516			$	(924,264	)	$	2,730,252			$	2,515,472	$	(901,903	)	$	1,613,569
	Acquired customer-related intangibles		15-20		8,174,959				(1,488,667		)	6,686,292				6,596,097		(1,429,572		)	5,166,525
	Acquired customer-related intangibles		15-20		8,174,959				(1,488,667		)	6,686,292				6,596,097		(1,429,572		)	5,166,525
	Acquired licenses and other intangibles		20-Mar		36,858				(4,342		)	32,516				43,012		(3,514		)	39,498
	Acquired licenses and other intangibles		20-Mar		36,858				(4,342		)	32,516				43,012		(3,514		)	39,498
	Economic Rights, TV Azteca		70		24,671				(12,584		)	12,087				25,522		(12,960		)	12,562
	Economic Rights, TV Azteca		70		24,671				(12,584		)	12,087				25,522		(12,960		)	12,562
	Total				$	11,891,004			$	(2,429,857	)	$	9,461,147			$	9,180,103	$	(2,347,949	)	$	6,832,154
	Total				$	11,891,004			$	(2,429,857	)	$	9,461,147			$	9,180,103	$	(2,347,949	)	$	6,832,154
	Deferred financing costs, net (3)		N/A									75,635									75,889
	Deferred financing costs, net (3)		N/A									75,635									75,889
	Other intangible assets, net											$	9,536,782								$	6,908,043
	Other intangible assets, net											$	9,536,782								$	6,908,043

	-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 which 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 March 31, 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 its Annual Report on Form 10-K for the year ended December 31, 2014, was approximately 16 years. Amortization of intangible assets for the three months ended March 31, 2015 and 2014 was approximately $110.5 million and $102.6 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 next five subsequent years (in millions):



	Fiscal Year
	2015 (remaining year)	$	422.9
	2015 (remaining year)	$	422.9
	2016	558.5
	2016	558.5
	2017	556.8
	2017	556.8
	2018	555.9
	2018	555.9
	2019	554
	2019	554
2020	549.9
2020	549.9

Accrued_Expenses

Accrued Expenses	3 Months Ended
	Mar. 31, 2015
Accrued Liabilities, Current [Abstract]
Accrued Expenses	Accrued Expenses
	Accrued expenses consisted of the following as of (in thousands):



		31-Mar-15		31-Dec-14
	Accrued property and real estate taxes	$	65,158	$	61,206

	Accrued rent	40,705		34,074

	Payroll and related withholdings	34,721		57,110

	Accrued construction costs	27,239		46,024

	Other accrued expenses	224,627		219,340

	Balance	$	392,450	$	417,754

LongTerm_Obligations_LongTerm_

Long-Term Obligations Long-Term Obligations	3 Months Ended
Long-Term Obligations Long-Term Obligations	Mar. 31, 2015
Debt Disclosure [Abstract]
Long-Term Obligations	Long-Term Obligations

	Current portion of long-term obligations—The Company’s current portion of long-term obligations primarily includes (i) 3.9 billion Mexican Pesos (“MXN”) (approximately $254.6 million) outstanding under the 5.2 billion MXN-denominated unsecured bridge loan (the “Mexican Loan”), which matures on May 1, 2015 and (ii) $500.0 million of the Company’s 7.000% senior notes due 2017 (the “7.000% Notes”), which were redeemed on April 29, 2015 (see note 16). The Company expects to repay the Mexican Loan 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”).
	Redemption of 4.625% Senior Notes—On February 11, 2015, the Company redeemed all of the outstanding 4.625% senior notes due 2015 (the “4.625% Notes”) 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. As a result, the Company recorded a loss on retirement of long-term obligations in the accompanying condensed consolidated statements of operations of $3.7 million, which included prepayment consideration and the remaining portion of the unamortized discount and deferred financing costs. The redemption was funded with borrowings under the 2013 Credit Facility. Upon completion of this redemption, none of the 4.625% Notes remained outstanding.

	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 Economico e Social, 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.

	2014 Credit Facility—During the three months ended March 31, 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 for an additional $500.0 million. As a result, as of March 31, 2015, the Company has the ability to borrow up to $2.0 billion under the 2014 Credit Facility.

	During the three months ended March 31, 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. As of March 31, 2015, the Company had $1.98 billion outstanding under the 2014 Credit Facility and $7.5 million of undrawn letters of credit. The Company maintains the ability to draw down and repay amounts under the 2014 Credit Facility in the ordinary course.

	The 2014 Credit Facility has a term of approximately five years, matures on January 31, 2020 and includes two optional renewal periods. The 2014 Credit Facility does 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 current margin over the London Interbank Offered Rate (“LIBOR”) that the Company incurs on borrowings is 1.250%, and the current commitment fee on the undrawn portion of the 2014 Credit Facility is 0.150%.

	2013 Credit Facility—During the three months ended March 31, 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 for an additional $750.0 million. As a result, as of March 31, 2015, the Company has the ability to borrow up to $2.75 billion under the 2013 Credit Facility.

	During the three months ended March 31, 2015, the Company borrowed an aggregate of $1.0 billion, which it primarily used to fund a portion of the Verizon Transaction, and repaid an aggregate of $615.0 million of revolving indebtedness under the 2013 Credit Facility. As of March 31, 2015, the Company had $400.0 million outstanding under the 2013 Credit Facility and $3.2 million of undrawn letters of credit. The Company maintains the ability to draw down and repay amounts under the 2013 Credit Facility in the ordinary course. In April 2015, the Company borrowed an additional $1.6 billion under the 2013 Credit Facility.

	The 2013 Credit Facility has a term of five years, matures on June 28, 2018 and includes two optional one-year renewal periods. The 2013 Credit Facility does 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 current margin over LIBOR that the Company incurs on borrowings is 1.250%, and the current commitment fee on the undrawn portion of the 2013 Credit Facility is 0.150%.

	2013 Term Loan—In October 2013, the Company entered into an unsecured term loan (the “2013 Term Loan”). The 2013 Term Loan matures on January 3, 2019. The current interest rate under the 2013 Term Loan is LIBOR plus 1.250%. During the three months ended March 31, 2015, the maximum Incremental Term Loan Commitments (as defined in the agreement) was increased to $1.0 billion. Effective February 20, 2015, the Company received an additional $500.0 million under the 2013 Term Loan. As a result, as of March 31, 2015, the Company had $2.0 billion outstanding under the 2013 Term Loan.

	Amendments to Bank Facilities—During the three months ended March 31, 2015, the Company entered into amendment agreements with respect to the 2014 Credit Facility, the 2013 Credit Facility and the 2013 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) 7.25 to 1.00 for the fiscal quarters ended March 31, 2015 and June 30, 2015, (ii) 7.00 to 1.00 for the fiscal quarters ended September 30, 2015 and December 31, 2015 and (iii) 6.00 to 1.00 thereafter.

Derivative_Financial_Instrumen

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2015
Summary of Derivative Instruments [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments
	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.
	South Africa
	One of the Company’s South African subsidiaries has 15 interest rate swap agreements outstanding, which mature on the earlier of termination of the underlying debt or March 31, 2020. These swap agreements provide that the Company pay a fixed interest rate ranging from 6.09% to 7.83% and receive variable interest at the three-month Johannesburg Interbank Agreed Rate (JIBAR) over the term of the interest rate swap agreements. The notional value is reduced in accordance with the repayment schedule under the related credit agreement.
	Colombia
	In connection with entering into a Colombian Peso (“COP”) denominated credit facility in October 2014 (the “Colombian Credit Facility”), one of the Company’s Colombian subsidiaries entered into an interest rate swap agreement with certain of the lenders under the Colombian Credit Facility. These swap agreement matures on the earlier of termination of the underlying debt or April 24, 2021 and provides that the Company pay a fixed interest rate of 5.74% and receive variable interest at the three-month Inter-bank Rate (“IBR”) over the term of the agreement. The notional value is reduced in accordance with the repayment schedule under the Colombian Credit Facility.
	The notional amount and fair value of the interest rate swap agreements were as follows (in thousands):


		31-Mar-15					31-Dec-14
		Local		USD			Local		USD
	South Africa (ZAR)
	Notional	430,978		35,524			440,614		38,080

	Fair Value	(173	)	(14	)		1,016		88

	Colombia (COP)
	Notional	98,750,000		38,334			100,000,000		41,798

	Fair Value	(3,313,103	)	(1,286	)		(1,548,688	)	(647	)

	As of March 31, 2015, the interest rate swap agreements were in liability positions and were included in Other non-current liabilities on the condensed consolidated balance sheets. As of December 31, 2014, the South African agreements were in asset positions and were included in Notes receivable and other non-current assets on the condensed consolidated balance sheets, and the Colombian agreement was in a liability position and included in Other non-current liabilities on the condensed consolidated balance sheets.
	In addition to the interest rate swap agreements, the Company was amortizing the settlement cost of a treasury rate lock as additional interest expense over the term of the 7.000% Notes.
	During the three months ended March 31, 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):


	Three months ended March 31,	Gain(Loss) Recognized in OCI - Effective Portion		Gain(Loss)		Location of Gain(Loss) Reclassified from AOCI into Income- Effective Portion		Gain(Loss) Recognized		Location of Gain(Loss) Recognized in Income -
				Reclassified from				in Income - Ineffective Portion		Ineffective Portion
				AOCI into
				Income -
				Effective Portion
	2015	($993)		($411)		Interest Expense		N/A		N/A

	2014	($587)		($969)		Interest Expense		N/A		N/A
	As of March 31, 2015, approximately $0.8 million of the amount related to derivatives designated as cash flow hedges and recorded in AOCI was expected to be reclassified into earnings in the next twelve months.

	For additional information on the Company’s interest rate swap agreements, see note 7.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 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):


		March 31, 2015
		Fair Value Measurements Using								Assets/Liabilities
		Level 1		Level 2				Level 3		at Fair Value
	Assets:
	Short-term investments (1)			$	14,394					$	14,394

	Liabilities:
	Acquisition-related contingent consideration							$	27,203	$	27,203

	Interest rate swap agreements			$	1,300					$	1,300




		31-Dec-14
		Fair Value Measurements Using								Assets/Liabilities
		Level 1		Level 2				Level 3		at Fair Value
	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 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.

	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 these unobservable inputs could significantly impact the fair value of the liabilities recorded in the accompanying condensed consolidated balance sheets and adjustments recorded in the condensed consolidated statements of operations.
	As of March 31, 2015, the Company estimated the value of all potential acquisition-related contingent consideration required payments to be between zero and $38.4 million. During the three months ended March 31, 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	1,194				—

	Settlements	(1,026		)		(615		)
	Change in fair value	—				582

	Foreign currency translation adjustment	(1,489		)		(515		)
	Balance as of March 31	$	27,203			$	31,342

Items Measured at Fair Value on a Nonrecurring Basis
Assets Held and Used—The Company’s long-lived assets are measured at fair value on a nonrecurring basis using Level 3 inputs. During the three months ended March 31, 2015 and 2014, the Company did not record any asset impairment charges.

There were no other items measured at fair value on a nonrecurring basis during the three months ended March 31, 2015.

During the year ended December 31, 2014, NII Holdings, Inc. (“NII”), a U.S. corporation, filed for Chapter 11 bankruptcy protection on behalf of itself and certain of its subsidiaries. NII is the ultimate parent company of certain operating subsidiaries in Brazil, Chile and Mexico that collectively represented approximately 5% of the Company’s consolidated revenues for the three months ended March 31, 2015. None of these subsidiaries were included in NII’s Chapter 11 filing. The Company did not identify any indicators of impairment as of March 31, 2015.
Fair Value of Financial Instruments—The Company’s financial instruments for which the carrying value reasonably approximates fair value at March 31, 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 March 31, 2015, the carrying value and fair value of long-term obligations, including the current portion, were $15.7 billion and $16.3 billion, respectively, of which $9.2 billion was measured using Level 1 inputs and $7.1 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_Comprehensiv

Accumulated Other Comprehensive Loss	3 Months Ended
	Mar. 31, 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 March 31, 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
								Currency
								Items
	Balance as of January 1, 2015	$	(1,345	)	$	(2,231	)	$	(790,645	)	$	(794,221	)
	Other comprehensive loss before reclassifications, net of tax	(909		)	—			(411,102		)	(412,011		)

	Amounts reclassified from accumulated other comprehensive loss, net of tax	172			200			—			372

	Net current-period other comprehensive (loss) income	(737		)	200			(411,102		)	(411,639		)

	Balance as of March 31, 2015	$	(2,082	)	$	(2,031	)	$	(1,201,747	)	$	(1,205,860	)



		Unrealized Losses on Cash Flow Hedges			Deferred Loss on the Settlement of the Treasury Rate Lock			Foreign			Total
								Currency
								Items
	Balance as of January 1, 2014	$	(1,869	)	$	(3,029	)	$	(306,322	)	$	(311,220	)
	Other comprehensive loss before reclassifications, net of tax	(780		)	—			38,711			37,931

	Amounts reclassified from accumulated other comprehensive loss, net of tax	679			200			—			879

	Net current-period other comprehensive (loss) income	(101		)	200			38,711			38,810

	Balance as of March 31, 2014	$	(1,970	)	$	(2,829	)	$	(267,611	)	$	(272,410	)

	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 months ended March 31, 2015 and 2014, respectively, is included in Income tax provision.

Income_Taxes

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 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 addition, in 2013 the Company acquired MIP Tower Holdings LLC (“MIPT”), which has been organized and has qualified as a REIT. For so long as MIPT continues to elect separate REIT status, it is independently subject to, and must comply with, the same REIT requirements that the Company must satisfy in order to qualify for taxation as a REIT.
	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 March 31, 2015 and December 31, 2014, the total amount of unrecognized tax benefits that would impact the effective tax rate, if recognized, was approximately $30.8 million and $31.9 million, respectively. The decrease in the amount of unrecognized tax benefits during the three months ended March 31, 2015 was primarily attributable to fluctuations in foreign currency exchange rates, partially offset by additions to the Company’s existing tax positions. 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 its Annual Report on Form 10-K for the year ended December 31, 2014. The impact of the amount of such changes to previously recorded uncertain tax positions could range from zero to $16.2 million.
	The Company recorded penalties and income tax-related interest expense during the three months ended March 31, 2015 and 2014 of $0.9 million and $1.3 million, respectively. As of March 31, 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 $24.0 million and $24.9 million, respectively.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 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 months ended March 31, 2015 and 2014 of $29.9 million and $24.6 million, respectively. The Company capitalized $0.5 million and $0.4 million of stock-based compensation expense as property and equipment during the three months ended March 31, 2015 and 2014, respectively.
	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 March 31, 2015, the Company had the ability to grant stock-based awards with respect to an aggregate of 11.5 million shares of common stock under the 2007 Plan.
	The Company’s Compensation Committee adopted a death, disability and retirement benefits program in connection with equity awards granted on or after January 1, 2013, that 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 three months ended March 31, 2015 was as follows:


		Number of
		Options
	Outstanding as of January 1, 2015	6,508,435

	Granted	1,994,079

	Exercised	(88,310	)
	Forfeited	(38,911	)
	Expired	(1,200	)
	Outstanding as of March 31, 2015	8,374,093


	The fair value of each option granted during the three months ended March 31, 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		1.57% - 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 three months ended March 31, 2015 was $15.09. As of March 31, 2015, total unrecognized compensation expense related to unvested stock options was $49.1 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 three months ended March 31, 2015 was as follows:


		RSUs			PSUs (1)
	Outstanding as of January 1, 2015	1,758,817			—

	Granted	682,256			23,379

	Vested	(651,253	)		—

	Forfeited	(22,094	)		—

	Outstanding as of March 31, 2015	1,767,726			23,379

	(1) Represents the target number of shares issuable at the end of the three-year performance cycle based on performance in the first year.

	Restricted Stock Units—As of March 31, 2015, total unrecognized compensation expense related to unvested RSUs granted under the 2007 Plan was $116.0 million and is expected to be recognized over a weighted average period of approximately three years.

	Performance-Based Restricted Stock Units—During the three months ended March 31, 2015, the Company 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 months ended March 31, 2015, the Company recorded $0.1 million 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 March 31, 2015 was $1.7 million based on the Company’s current assessment of probability of achieving the performance goals. The weighted-average period over which the cost will be recognized is one year.

Equity

3 Months Ended

Mar. 31, 2015

Equity [Abstract]

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 (or an authorized committee thereof) 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—On May 12, 2014, the Company issued 6,000,000 shares 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 (or an authorized committee thereof) 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.

Stock Repurchase Program—In March 2011, the Board of Directors approved a stock repurchase program, pursuant to which the Company is authorized to purchase up to $1.5 billion of common stock (the “2011 Buyback”). As of March 31, 2015, the Company had $1.1 billion remaining under the 2011 Buyback. In September 2013, the Company temporarily suspended repurchases.

Sales of Equity Securities—The Company receives proceeds from sales of its equity securities pursuant to its employee stock purchase plan and upon exercise of stock options granted under its equity incentive plans. During the three months ended March 31, 2015, the Company received an aggregate of $5.1 million in proceeds upon exercises of stock options.

Distributions—During the three months ended March 31, 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

2-Dec-14

13-Jan-15

16-Dec-14

0.38

150.7

March 5, 2015

April 28, 2015

April 10, 2015

0.42

177.7

Series A Preferred Stock

2-Dec-14

16-Feb-15

1-Feb-15

1.3125

7.9

The Company accrues distributions on unvested restricted stock units granted subsequent to January 1, 2012, which are payable upon vesting. As of March 31, 2015, the amount accrued for distributions payable related to unvested restricted stock units was $3.0 million. During the three months ended March 31, 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 be subject to adjustment by the Company’s Board of Directors.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 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 (i) upon the vesting of restricted stock awards, (ii) upon exercise of stock options and (iii) upon 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 months ended March 31, 2015 and 2014 (in thousands, except per share data):


		Three Months Ended March 31,
		2015				2014
	Net income attributable to American Tower Corporation stockholders	$	193,317			$	202,499

	Dividends on preferred stock	(9,819		)		—

	Net income attributable to American Tower Corporation common stockholders	183,498				202,499

	Basic weighted average common shares outstanding	405,111				395,146

	Dilutive securities	4,288				3,974

	Diluted weighted average common shares outstanding	409,399				399,120

	Basic net income attributable to American Tower Corporation common stockholders per common share	$	0.45			$	0.51

	Diluted net income attributable to American Tower Corporation common stockholders per common share	$	0.45			$	0.51


	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 March 31,
		2015			2014
	Restricted stock awards	3			—

	Stock options	501			1,708

	Preferred stock	9,194			—

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 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 to the tenant leases that were in place on such sites at the time of the transaction. The total estimated future minimum rental receipts under the non-cancellable Verizon leases and in-place third-party leases is approximately $3.0 billion and is 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 CPI 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. The Company’s future minimum rental payments under non-cancellable operating leases, including certain renewal periods related to the Verizon communications sites is approximately $2.2 billion and is 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 sublease for such tranche plus the fair market value of certain alterations made to the related towers by Verizon. 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 sublease for that site plus the fair market value of certain alterations made to the related tower by AT&T. As of March 31, 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 $659.4 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 $73.7 million as of March 31, 2015. At Verizon Wireless’s option, at the expiration of the sublease, the purchase price would be payable in cash or with 769 shares of the Company’s common stock per tower, which would be valued at approximately $128.2 million in the aggregate based on the closing price at March 31, 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 Indian Rupees (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 (“ETIPL”), and more specifically involving the issuance of share capital and the determination by the tax authority that an income tax obligation arose as a result of such issuance. The assessment was made with respect to transactions that took place in the tax year commencing in 2008, prior to the Company’s acquisition of ETIPL. Under the Company’s definitive acquisition agreement of ETIPL, the seller is obligated to indemnify and defend the Company with respect to any tax-related liability that may arise from activities prior to March 31, 2010. 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. The tax authority has the right to appeal this decision in accordance with applicable Indian law.

Acquisitions_and_Other_Transac

Acquisitions and Other Transactions	3 Months Ended
	Mar. 31, 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, including contingent consideration, and 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 will evaluate 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 three months ended March 31, 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 months ended March 31, 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, depending on its size and nature, 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 March 31, 2015 was approximately $4.5 million and $2.1 million, respectively. The revenues and gross margin amounts also reflect incremental revenues from the addition of new tenants to such sites subsequent to the transaction date. Incremental amounts of segment selling, general, administrative and development expense 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 costs in the period in which they are incurred and services are received. Acquisition and merger related costs 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, and are included in Other operating expenses in the condensed consolidated statements of operations. During the three months ended March 31, 2015 and 2014, the Company recognized acquisition and merger related expenses of $3.0 million and $9.8 million, respectively. In addition, during the three months ended March 31, 2015 and 2014, the Company recorded $1.8 million and $2.5 million, respectively, of integration costs related to recently closed acquisitions.

	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 (the “Master Agreement”) and the related Master Prepaid Lease, Management Agreement, Sale Site Master Lease Agreement and MPL Site Master Lease Agreement.

	The Company, through its wholly-owned subsidiary, leased or subleased from certain Verizon subsidiaries 11,285 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 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 additional 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 (see note 11), (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 March 31, 2015 and represent the asset balances of the capital lease.


	Current assets		$	13,112

	Non-current assets		208,492

	Property and equipment		2,031,657

	Intangible assets (1):
	Customer-related intangible assets		1,742,824

	Network location intangible assets		1,179,409

	Current liabilities		(10,747		)
	Other non-current liabilities (2)		(200,530		)
	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) 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, $4.7 million of which was paid during the three months ended March 31, 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
	International Acquisitions—During the three months ended March 31, 2015, the Company acquired a total of six communications sites and related assets for an aggregate purchase price of $0.5 million, which was satisfied by the issuance of credits to be applied against trade accounts receivable. The purchase price is subject to post-closing adjustments.
	U.S. Acquisitions—During the three months ended March 31, 2015, the Company acquired a total of 190 communications sites and equipment, as well as three property interests, in the United States for an aggregate purchase price of $121.3 million (including $1.2 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 further above. The purchase price is 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 March 31, 2015.


			International				U.S.
	Current assets		$	—			$	164

	Non-current assets		—				1,000

	Property and equipment		504				29,730

Intangible assets (1):
Customer-related intangible assets		—				48,190

Network location intangible assets		—				34,850

Current liabilities		—				(238		)

Other non-current liabilities		(13		)		(1,946		)
Net assets acquired		491				111,750

Goodwill (2)		—				9,548

Fair value of net assets acquired		491				121,298

Debt assumed		—				—

Purchase Price		$	491			$	121,298



-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 domestic rental and management segment and the Company expects goodwill recorded will be deductible for tax purposes.

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 and paid approximately $61.1 million to acquire all outstanding preferred equity. In addition, the Company assumed approximately $261.1 million of BR Towers’ existing indebtedness and has repaid approximately $135.6 million of principal balance subsequent to closing, including the repayment of $13.5 million during the three months ended March 31, 2015. The purchase price is subject to post-closing adjustments.

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 three months ended March 31, 2015. In addition, the Company assumed $196.5 million of Richland’s existing indebtedness. In June 2014, the Company repaid the outstanding indebtedness, paid prepayment consideration and wrote-off the unamortized premium associated with the fair value adjustment.

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 price is 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		$	32,070			$	8,583		$	797

Non-current assets		9,135				—			—

Property and equipment		141,422				154,899			38,413

Intangible assets (2):
Customer-related intangible assets		495,279				186,455			89,990

Network location intangible assets		136,233				3,409			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		726,365				346,789			164,998

Goodwill (3)		164,717				44,128			15,824

Fair value of net assets acquired		891,082				390,917			180,822

Debt assumed (4)		(261,136		)		(201,999		)	—

Preferred stock outstanding		(61,056		)		—			—

Purchase Price		$	568,890			$	188,918		$	180,822

(1) The allocation of the purchase price was finalized during the three months ended March 31, 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 domestic and international rental and management segments, as applicable, 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.

Unless otherwise noted, 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 Company’s Annual Report on Form 10-K for the year ended December 31, 2014.



		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 domestic and international rental and management segments, as applicable, 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) BR Towers debt assumed 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 March 31,
		2015				2014
Pro forma revenues		$	1,170,772			$	1,115,001

Pro forma net income attributable to American Tower Corporation common stockholders		$	145,137			$	147,760

Pro forma net income per common share amounts:
Basic net income attributable to American Tower Corporation common stockholders		$	0.34			$	0.35

Diluted net income attributable to American Tower Corporation common stockholders		$	0.34			$	0.35


Other Signed Acquisitions

TIM Acquisition—On November 21, 2014, the Company entered into an agreement with TIM Celular S.A. (“TIM”), a wholly-owned subsidiary of TIM Participações S.A., a publicly traded subsidiary of Telecom Italia S.p.A., to acquire two portfolios of communications sites in Brazil, subject to customary closing conditions. The first portfolio includes approximately 5,240 communications sites and the second portfolio includes approximately 1,240 communications sites. The Company closed on an initial tranche of communications sites on April 29, 2015 (see note 16).
Airtel Acquisition—On November 24, 2014, the Company and Airtel Networks Limited entered into a definitive agreement, through Bharti Airtel Limited’s subsidiary company, Bharti Airtel International (Netherlands) BV (“Airtel”), for the sale of over 4,800 of Airtel’s communications towers in Nigeria, subject to customary closing conditions and regulatory approval. At signing, the total purchase price was approximately $1.1 billion, subject to adjustments.
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 Costa Rica and 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):


		Maximum				Estimated value at			Additions (3)			Settlements
		potential value (1)				March 31, 2015 (2)
Colombia		$	27,440			$	18,328		$	—		$	—

Costa Rica		3,960				1,898			—			—

Ghana		470				470			—			—

United States		6,507				6,507			1,194			(1,026		)

Total		$	38,377			$	27,203		$	1,194		$	(1,026	)

(1) The maximum potential value is based on current exchange rates. The minimum value could be zero.
(2) Estimate is determined using a probability weighted average of expected outcomes as of March 31, 2015.
(3) Based on preliminary acquisition accounting upon closing of certain acquisitions during three months ended March 31, 2015.

For more information regarding contingent consideration, see note 7.

Business_Segments

Business Segments	3 Months Ended
	Mar. 31, 2015
Segment Reporting, Measurement Disclosures [Abstract]
Business Segments	Business Segments
	The Company operates in three business 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 March 31, 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, Peru, South Africa and Uganda. In November 2014, the Company signed an agreement to acquire communications sites in Nigeria.
	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 its Annual Report on Form 10-K for the year ended December 31, 2014. 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 months ended March 31, 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			Network			Other			Total
								Management			Development
	Three months ended March 31, 2015	Domestic			International						Services
		(in thousands)
	Segment revenues	$	717,880		$	344,300		$	1,062,180		$	17,010					$	1,079,190

	Segment operating expenses (1)	133,032			125,793			258,825			5,244						264,069

	Interest income, TV Azteca, net	—			2,596			2,596			—						2,596

	Segment gross margin	584,848			221,103			805,951			11,766						817,717

	Segment selling, general, administrative and development expense (1)	26,822			34,611			61,433			3,436						64,869

	Segment operating profit	$	558,026		$	186,492		$	744,518		$	8,330					$	752,848

	Stock-based compensation expense													$	29,861		29,861

	Other selling, general, administrative and development expense													29,131			29,131

	Depreciation, amortization and accretion													263,520			263,520

	Other expense (principally interest expense and other expenses)													210,972			210,972

	Income from continuing operations before income taxes																$	219,364

	Total assets	$	19,560,579		$	6,211,823		$	25,772,402		$	67,226		$	90,566		$	25,930,194


	-1	Segment operating expenses and segment selling, general, administrative and development expenses exclude stock-based compensation expense of $0.6 million and $29.3 million, respectively.



		Rental and Management						Total Rental and			Network			Other			Total
								Management			Development
	Three months ended March 31, 2014	Domestic			International						Services
		(in thousands)
	Segment revenues	$	635,779		$	324,341		$	960,120		$	23,969					$	984,089

	Segment operating expenses (1)	121,509			128,954			250,463			9,802						260,265

	Interest income, TV Azteca, net	—			2,595			2,595			—						2,595

	Segment gross margin	514,270			197,982			712,252			14,167						726,419

	Segment selling, general, administrative and development expense (1)	27,409			29,216			56,625			2,530						59,155

	Segment operating profit	$	486,861		$	168,766		$	655,627		$	11,637					$	667,264

	Stock-based compensation expense													$	24,604		24,604

	Other selling, general, administrative and development expense													26,774			26,774

Depreciation, amortization and accretion													245,763			245,763

Other expense (principally interest expense and other (expense) income)													159,161			159,161

Income from continuing operations before income taxes																$	210,962

Total assets	$	13,527,578		$	6,622,829		$	20,150,407		$	65,417		$	201,583		$	20,417,407


-1	Segment operating expenses and segment selling, general, administrative and development expenses exclude stock-based compensation expense of $0.5 million and $24.1 million, respectively.

Subsequent_Events

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events

	Redemption of 7.000% Senior Notes—On April 29, 2015, the Company redeemed all of the outstanding 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. The Company expects to record a loss on retirement of long-term obligations of approximately $74.3 million. The redemption was funded with borrowings under the Company’s existing credit facilities and cash on hand. Upon completion of this redemption, none of the 7.000% Notes remained outstanding.
	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). In connection with this closing, the amount of the letters of credit with Banco Santander was reduced to approximately 92.1 million BRL, corresponding to certain obligations related to the Company’s acquisition agreement.

Description_of_Business_Basis_1

Description of Business, Basis of Presentation and Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 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 on January 1, 2018. 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 during the three months ended March 31, 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. The update requires retrospective application and the update is effective for annual reporting periods beginning after December 15, 2015. The Company does not expect the adoption of this guidance to have a material effect on its financial statements.

Prepaid_and_Other_Current_Asse1

Prepaid and Other Current Assets (Tables)	3 Months Ended
	Mar. 31, 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):



		31-Mar-15		December 31, 2014 (1)
	Prepaid operating ground leases	$	94,254	$	88,508

	Prepaid income tax	39,022		34,512

	Prepaid assets	33,919		23,848

	Unbilled receivables	26,763		25,352

	Value added tax and other consumption tax receivables	21,920		23,228

	Other miscellaneous current assets	53,303		59,635

	Balance	$	269,181	$	255,083

	(1) December 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
Goodwill and Other Intangible Assets (Tables)	Mar. 31, 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			Total
			Rental and Management							Development
			Domestic			International				Services
	Balance as of January 1, 2015 (1)		$	3,353,851		$	672,710			$	1,988		$	4,028,549
	Balance as of January 1, 2015 (1)		$	3,353,851		$	672,710			$	1,988		$	4,028,549
	Additions		9,548			—				—			9,548
	Additions		9,548			—				—			9,548
	Effect of foreign currency translation		—			(57,923		)		—			(57,923		)
	Effect of foreign currency translation		—			(57,923		)		—			(57,923		)
	Balance as of March 31, 2015		$	3,363,399		$	614,787			$	1,988		$	3,980,174
	Balance as of March 31, 2015		$	3,363,399		$	614,787			$	1,988		$	3,980,174

	-1	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):



					31-Mar-15											December 31, 2014 (1)
			Estimated		Gross				Accumulated			Net Book				Gross		Accumulated			Net Book
			Useful		Carrying				Amortization			Value				Carrying		Amortization			Value
			Lives		Value											Value
			(years)
	Acquired network location intangibles (2)		Up to 20		$	3,654,516			$	(924,264	)	$	2,730,252			$	2,515,472	$	(901,903	)	$	1,613,569
	Acquired network location intangibles (2)		Up to 20		$	3,654,516			$	(924,264	)	$	2,730,252			$	2,515,472	$	(901,903	)	$	1,613,569
	Acquired customer-related intangibles		15-20		8,174,959				(1,488,667		)	6,686,292				6,596,097		(1,429,572		)	5,166,525
	Acquired customer-related intangibles		15-20		8,174,959				(1,488,667		)	6,686,292				6,596,097		(1,429,572		)	5,166,525
	Acquired licenses and other intangibles		20-Mar		36,858				(4,342		)	32,516				43,012		(3,514		)	39,498
	Acquired licenses and other intangibles		20-Mar		36,858				(4,342		)	32,516				43,012		(3,514		)	39,498
	Economic Rights, TV Azteca		70		24,671				(12,584		)	12,087				25,522		(12,960		)	12,562
	Economic Rights, TV Azteca		70		24,671				(12,584		)	12,087				25,522		(12,960		)	12,562
	Total				$	11,891,004			$	(2,429,857	)	$	9,461,147			$	9,180,103	$	(2,347,949	)	$	6,832,154
	Total				$	11,891,004			$	(2,429,857	)	$	9,461,147			$	9,180,103	$	(2,347,949	)	$	6,832,154
	Deferred financing costs, net (3)		N/A									75,635									75,889
	Deferred financing costs, net (3)		N/A									75,635									75,889
	Other intangible assets, net											$	9,536,782								$	6,908,043
	Other intangible assets, net											$	9,536,782								$	6,908,043

	-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 next five subsequent years (in millions):



	Fiscal Year
	2015 (remaining year)	$	422.9
	2015 (remaining year)	$	422.9
	2016	558.5
	2016	558.5
	2017	556.8
	2017	556.8
	2018	555.9
	2018	555.9
	2019	554
	2019	554
	2020	549.9
	2020	549.9

Accrued_Expenses_Tables

Accrued Expenses (Tables)	3 Months Ended
	Mar. 31, 2015
Accrued Liabilities, Current [Abstract]
Schedule of accrued liabilities	Accrued expenses consisted of the following as of (in thousands):



		31-Mar-15		31-Dec-14
	Accrued property and real estate taxes	$	65,158	$	61,206

	Accrued rent	40,705		34,074

	Payroll and related withholdings	34,721		57,110

	Accrued construction costs	27,239		46,024

	Other accrued expenses	224,627		219,340

	Balance	$	392,450	$	417,754

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 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):


		31-Mar-15					31-Dec-14
		Local		USD			Local		USD
	South Africa (ZAR)
	Notional	430,978		35,524			440,614		38,080

	Fair Value	(173	)	(14	)		1,016		88

	Colombia (COP)
	Notional	98,750,000		38,334			100,000,000		41,798

	Fair Value	(3,313,103	)	(1,286	)		(1,548,688	)	(647	)
Schedule of interest rate swap agreements' impact on other comprehensive income	During the three months ended March 31, 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):


	Three months ended March 31,	Gain(Loss) Recognized in OCI - Effective Portion		Gain(Loss)		Location of Gain(Loss) Reclassified from AOCI into Income- Effective Portion		Gain(Loss) Recognized		Location of Gain(Loss) Recognized in Income -
				Reclassified from				in Income - Ineffective Portion		Ineffective Portion
				AOCI into
				Income -
				Effective Portion
	2015	($993)		($411)		Interest Expense		N/A		N/A

	2014	($587)		($969)		Interest Expense		N/A		N/A

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 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):


		March 31, 2015
		Fair Value Measurements Using									Assets/Liabilities
		Level 1		Level 2				Level 3			at Fair Value
	Assets:
	Short-term investments (1)			$	14,394						$	14,394

	Liabilities:
	Acquisition-related contingent consideration							$	27,203		$	27,203

	Interest rate swap agreements			$	1,300						$	1,300




		31-Dec-14
		Fair Value Measurements Using									Assets/Liabilities
		Level 1		Level 2				Level 3			at Fair Value
	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 March 31, 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	1,194				—

	Settlements	(1,026		)		(615		)
	Change in fair value	—				582

	Foreign currency translation adjustment	(1,489		)		(515		)
	Balance as of March 31	$	27,203			$	31,342

	A summary of the value of the Company’s contingent consideration is as follows (in thousands):


			Maximum				Estimated value at			Additions (3)			Settlements
			potential value (1)				March 31, 2015 (2)
	Colombia		$	27,440			$	18,328		$	—		$	—

	Costa Rica		3,960				1,898			—			—

	Ghana		470				470			—			—

	United States		6,507				6,507			1,194			(1,026		)

	Total		$	38,377			$	27,203		$	1,194		$	(1,026	)

	(1) The maximum potential value is based on current exchange rates. The minimum value could be zero.
	(2) Estimate is determined using a probability weighted average of expected outcomes as of March 31, 2015.
	(3) Based on preliminary acquisition accounting upon closing of certain acquisitions during three months ended March 31, 2015.

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Loss (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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
								Currency
								Items
	Balance as of January 1, 2015	$	(1,345	)	$	(2,231	)	$	(790,645	)	$	(794,221	)
	Other comprehensive loss before reclassifications, net of tax	(909		)	—			(411,102		)	(412,011		)

	Amounts reclassified from accumulated other comprehensive loss, net of tax	172			200			—			372

	Net current-period other comprehensive (loss) income	(737		)	200			(411,102		)	(411,639		)

	Balance as of March 31, 2015	$	(2,082	)	$	(2,031	)	$	(1,201,747	)	$	(1,205,860	)



		Unrealized Losses on Cash Flow Hedges			Deferred Loss on the Settlement of the Treasury Rate Lock			Foreign			Total
								Currency
								Items
	Balance as of January 1, 2014	$	(1,869	)	$	(3,029	)	$	(306,322	)	$	(311,220	)
	Other comprehensive loss before reclassifications, net of tax	(780		)	—			38,711			37,931

	Amounts reclassified from accumulated other comprehensive loss, net of tax	679			200			—			879

	Net current-period other comprehensive (loss) income	(101		)	200			38,711			38,810

	Balance as of March 31, 2014	$	(1,970	)	$	(2,829	)	$	(267,611	)	$	(272,410	)

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2015 was as follows:


		Number of
		Options
	Outstanding as of January 1, 2015	6,508,435

	Granted	1,994,079

	Exercised	(88,310	)
	Forfeited	(38,911	)
	Expired	(1,200	)
	Outstanding as of March 31, 2015	8,374,093

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		1.57% - 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 three months ended March 31, 2015 was as follows:


		RSUs			PSUs (1)
	Outstanding as of January 1, 2015	1,758,817			—

	Granted	682,256			23,379

	Vested	(651,253	)		—

	Forfeited	(22,094	)		—

	Outstanding as of March 31, 2015	1,767,726			23,379

	(1) Represents the target number of shares issuable at the end of the three-year performance cycle based on performance in the first year.

Equity_Tables

Equity (Tables)

3 Months Ended

Mar. 31, 2015

Equity [Abstract]

Schedule of dividends payable

During the three months ended March 31, 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

2-Dec-14

13-Jan-15

16-Dec-14

0.38

150.7

March 5, 2015

April 28, 2015

April 10, 2015

0.42

177.7

Series A Preferred Stock

2-Dec-14

16-Feb-15

1-Feb-15

1.3125

7.9

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 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 months ended March 31, 2015 and 2014 (in thousands, except per share data):


		Three Months Ended March 31,
		2015				2014
	Net income attributable to American Tower Corporation stockholders	$	193,317			$	202,499

	Dividends on preferred stock	(9,819		)		—

	Net income attributable to American Tower Corporation common stockholders	183,498				202,499

	Basic weighted average common shares outstanding	405,111				395,146

	Dilutive securities	4,288				3,974

	Diluted weighted average common shares outstanding	409,399				399,120

	Basic net income attributable to American Tower Corporation common stockholders per common share	$	0.45			$	0.51

	Diluted net income attributable to American Tower Corporation common stockholders per common share	$	0.45			$	0.51

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	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 March 31,
		2015			2014
	Restricted stock awards	3			—

	Stock options	501			1,708

	Preferred stock	9,194			—

Acquisitions_and_Other_Transac1

Acquisitions and Other Transactions (Tables)	3 Months Ended
	Mar. 31, 2015
Business Combination, Description [Abstract]
Schedule of recognized identified assets acquired and liabilities assumed	he 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 Company’s Annual Report on Form 10-K for the year ended December 31, 2014.



			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 domestic and international rental and management segments, as applicable, 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) BR Towers debt assumed 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.

	Balances are reflected in the accompanying condensed consolidated balance sheets as of March 31, 2015 and represent the asset balances of the capital lease.


	Current assets		$	13,112

	Non-current assets		208,492

	Property and equipment		2,031,657

	Intangible assets (1):
	Customer-related intangible assets		1,742,824

	Network location intangible assets		1,179,409

	Current liabilities		(10,747		)
	Other non-current liabilities (2)		(200,530		)
	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) 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, $4.7 million of which was paid during the three months ended March 31, 2015.
	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 March 31, 2015.


		International				U.S.
Current assets		$	—			$	164

Non-current assets		—				1,000

Property and equipment		504				29,730

Intangible assets (1):
Customer-related intangible assets		—				48,190

Network location intangible assets		—				34,850

Current liabilities		—				(238		)

Other non-current liabilities		(13		)		(1,946		)
Net assets acquired		491				111,750

Goodwill (2)		—				9,548

Fair value of net assets acquired		491				121,298

Debt assumed		—				—

Purchase Price		$	491			$	121,298



-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 domestic rental and management segment and the Company expects goodwill recorded will be deductible for tax purposes.
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		$	32,070			$	8,583			$	797

Non-current assets		9,135				—				—

Property and equipment		141,422				154,899				38,413

Intangible assets (2):
Customer-related intangible assets		495,279				186,455				89,990

Network location intangible assets		136,233				3,409				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		726,365				346,789				164,998

Goodwill (3)		164,717				44,128				15,824

Fair value of net assets acquired		891,082				390,917				180,822

Debt assumed (4)		(261,136		)		(201,999		)		—

Preferred stock outstanding		(61,056		)		—				—

Purchase Price		$	568,890			$	188,918			$	180,822

(1) The allocation of the purchase price was finalized during the three months ended March 31, 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 domestic and international rental and management segments, as applicable, 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.
Business acquisition, 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 March 31,
			2015				2014
	Pro forma revenues		$	1,170,772			$	1,115,001

	Pro forma net income attributable to American Tower Corporation common stockholders		$	145,137			$	147,760

	Pro forma net income per common share amounts:
	Basic net income attributable to American Tower Corporation common stockholders		$	0.34			$	0.35

	Diluted net income attributable to American Tower Corporation common stockholders		$	0.34			$	0.35

Schedule of business acquisitions by acquisition, contingent consideration	During the three months ended March 31, 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	1,194				—

	Settlements	(1,026		)		(615		)
	Change in fair value	—				582

	Foreign currency translation adjustment	(1,489		)		(515		)
	Balance as of March 31	$	27,203			$	31,342

	A summary of the value of the Company’s contingent consideration is as follows (in thousands):


			Maximum				Estimated value at				Additions (3)			Settlements
			potential value (1)				March 31, 2015 (2)
	Colombia		$	27,440			$	18,328			$	—		$	—

	Costa Rica		3,960				1,898				—			—

	Ghana		470				470				—			—

	United States		6,507				6,507				1,194			(1,026		)

	Total		$	38,377			$	27,203			$	1,194		$	(1,026	)

	(1) The maximum potential value is based on current exchange rates. The minimum value could be zero.
	(2) Estimate is determined using a probability weighted average of expected outcomes as of March 31, 2015.
	(3) Based on preliminary acquisition accounting upon closing of certain acquisitions during three months ended March 31, 2015.

Business_Segments_Tables

Business Segments (Tables)	3 Months Ended
	Mar. 31, 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 months ended March 31, 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		Network		Other		Total
						Management		Development
	Three months ended March 31, 2015	Domestic		International				Services
		(in thousands)
	Segment revenues	$	717,880	$	344,300	$	1,062,180	$	17,010			$	1,079,190

	Segment operating expenses (1)	133,032		125,793		258,825		5,244				264,069

	Interest income, TV Azteca, net	—		2,596		2,596		—				2,596

	Segment gross margin	584,848		221,103		805,951		11,766				817,717

	Segment selling, general, administrative and development expense (1)	26,822		34,611		61,433		3,436				64,869

	Segment operating profit	$	558,026	$	186,492	$	744,518	$	8,330			$	752,848

	Stock-based compensation expense									$	29,861	29,861

	Other selling, general, administrative and development expense									29,131		29,131

	Depreciation, amortization and accretion									263,520		263,520

	Other expense (principally interest expense and other expenses)									210,972		210,972

	Income from continuing operations before income taxes											$	219,364

	Total assets	$	19,560,579	$	6,211,823	$	25,772,402	$	67,226	$	90,566	$	25,930,194


	-1	Segment operating expenses and segment selling, general, administrative and development expenses exclude stock-based compensation expense of $0.6 million and $29.3 million, respectively.



		Rental and Management				Total Rental and		Network		Other		Total
						Management		Development
	Three months ended March 31, 2014	Domestic		International				Services
		(in thousands)
	Segment revenues	$	635,779	$	324,341	$	960,120	$	23,969			$	984,089

	Segment operating expenses (1)	121,509		128,954		250,463		9,802				260,265

	Interest income, TV Azteca, net	—		2,595		2,595		—				2,595

	Segment gross margin	514,270		197,982		712,252		14,167				726,419

	Segment selling, general, administrative and development expense (1)	27,409		29,216		56,625		2,530				59,155

	Segment operating profit	$	486,861	$	168,766	$	655,627	$	11,637			$	667,264

	Stock-based compensation expense									$	24,604	24,604

	Other selling, general, administrative and development expense									26,774		26,774

	Depreciation, amortization and accretion									245,763		245,763

	Other expense (principally interest expense and other (expense) income)									159,161		159,161

	Income from continuing operations before income taxes											$	210,962

	Total assets	$	13,527,578	$	6,622,829	$	20,150,407	$	65,417	$	201,583	$	20,417,407


-1	Segment operating expenses and segment selling, general, administrative and development expenses exclude stock-based compensation expense of $0.5 million and $24.1 million, respectively.

Description_of_Business_Basis_2

Description of Business, Basis of Presentation and Accounting Policies (Narrative) (Details) (Verizon Transaction)	Mar. 27, 2015
	site
Verizon Transaction
Gain (Loss) on Investments [Line Items]
Number of sites acquired	11,448

Prepaid_and_Other_Current_Asse2

Prepaid and Other Current Assets (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid operating ground leases	$94,254	$88,508	[1]
Prepaid income tax	39,022	34,512	[1]
Prepaid assets	33,919	23,848	[1]
Unbilled receivables	26,763	25,352	[1]
Value added tax and other consumption tax receivables	21,920	23,228	[1]
Other miscellaneous current assets	53,303	59,635	[1]
Balance	$269,181	$255,083	[1]

[1]	DecemberÂ 31, 2014 balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Indefinite-lived Intangible Assets [Line Items]
Amortization of intangible assets	$110.50	$102.60
Weighted Average [Member]
Indefinite-lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Remaining Amortization Period	16 years

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets (Rollforward) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Goodwill [Roll Forward]
Balance as of January 1, 2015	$4,028,549	[1]
Additions	9,548
Effect of foreign currency translation	-57,923
Balance as of March 31, 2015	3,980,174
Rental And Management \| Domestic
Goodwill [Roll Forward]
Balance as of January 1, 2015	3,353,851	[1]
Additions	9,548
Effect of foreign currency translation	0
Balance as of March 31, 2015	3,363,399
Rental And Management \| International
Goodwill [Roll Forward]
Balance as of January 1, 2015	672,710	[1]
Additions	0
Effect of foreign currency translation	-57,923
Balance as of March 31, 2015	614,787
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 March 31, 2015	$1,988

[1]	Balances have been revised to reflect purchase accounting measurement period adjustments.

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets (Changes in the Carrying Value of Goodwill) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	$11,891,004		$9,180,103	[1]
Accumulated Amortization	-2,429,857		-2,347,949	[1]
Net Book Value	9,461,147		6,832,154	[1]
Deferred financing costs, net	75,635	[2]	75,889	[1],[2]
Other intangible assets, net	9,536,782		6,908,043	[1]
Estimated useful lives	11 years
Acquired Network Location Intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	3,654,516	[3]	2,515,472	[1],[3]
Accumulated Amortization	-924,264	[3]	-901,903	[1],[3]
Net Book Value	2,730,252	[3]	1,613,569	[1],[3]
Acquired Network Location Intangibles \| Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	20 years
Acquired Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	8,174,959		6,596,097	[1]
Accumulated Amortization	-1,488,667		-1,429,572	[1]
Net Book Value	6,686,292		5,166,525	[1]
Acquired Customer Relationships \| Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives	15 years
Acquired 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	36,858		43,012	[1]
Accumulated Amortization	-4,342		-3,514	[1]
Net Book Value	32,516		39,498	[1]
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	24,671		25,522	[1]
Accumulated Amortization	-12,584		-12,960	[1]
Net Book Value	$12,087		$12,562	[1]
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_Intangible_5

Goodwill and Other Intangible Assets (Expected Future Amortization Expenses) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2015 (remaining year)	$422.90
2016	558.5
2017	556.8
2018	555.9
2019	554
2020	$549.90

Accrued_Expenses_Details

Accrued Expenses (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
Accrued property and real estate taxes	$65,158	$61,206
Accrued rent	40,705	34,074
Payroll and related withholdings	34,721	57,110
Accrued construction costs	27,239	46,024
Other accrued expenses	224,627	219,340
Balance	$392,450	$417,754

LongTerm_Obligations_Narrative

Long-Term Obligations (Narrative) (Details)

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

0 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Dec. 31, 2014

Mar. 31, 2015

Feb. 12, 2015

Mar. 31, 2015

Nov. 19, 2014

Mar. 31, 2015

Feb. 20, 2015

Mar. 31, 2015

Feb. 20, 2015

Mar. 31, 2015

Sep. 20, 2014

Jun. 30, 2013

Mar. 31, 2015

Feb. 20, 2015

Jun. 30, 2013

Mar. 31, 2015

Sep. 20, 2014

Jun. 30, 2013

Apr. 29, 2015

Apr. 30, 2015

Feb. 20, 2015

USD ($)

Mexican loan

Seven Point Zero Zero Percent Senior Notes

Four Point Six Two Five Percent Senior Notes

BR Towers Credit Facility

Credit Facility 2014

Credit Facility 2013

Term Loan 2013

Senior Notes

Revolving Credit Facility

London Interbank Offered Rate (LIBOR)

Subsequent Event

Second measurement period

Third measurement period

Fourth measurement period

Unsecured Debt

Senior Notes

Unsecured Debt

Revolving Credit Facility

Unsecured Debt

Four Point Six Two Five Percent Senior Notes

USD ($)

Credit Facility 2014

Credit Facility 2013

Term Loan 2013

Revolving Credit Facility

Seven Point Zero Zero Percent Senior Notes

Revolving Credit Facility

Credit Facility 2014

Credit Facility 2013

Term Loan 2013

Credit Facility 2014

Credit Facility 2013

Term Loan 2013

Credit Facility 2014

Credit Facility 2013

Term Loan 2013

USD ($)

MXN

USD ($)

BRL

USD ($)

renewal_periods

USD ($)

Unsecured Debt

Credit Facility 2014

Credit Facility 2013

Senior Notes

Credit Facility 2013

Revolving Credit Facility

Unsecured Debt

Revolving Credit Facility

Unsecured Debt

Revolving Credit Facility

Unsecured Debt

renewal_periods

USD ($)

Debt Instrument [Line Items]

Long-term Debt

$2,000,000,000

Long-term Debt, Current Maturities

789,152,000

897,624,000

254,600,000

3,900,000,000

500,000,000

Proceeds from Lines of Credit

3,150,000,000

2,100,000,000

1,000,000,000

1,600,000,000

Bridge Loan

5,200,000,000

Stated percentage interest rate

7.00%

4.63%

7.00%

Debt Instrument, Redemption Price, Percentage

100.59%

Repayments of Senior Debt

613,600,000

571,700,000

Interest Paid

77,654,000

130,265,000

10,000,000

Extinguishment of Debt, Gain (Loss), Net of Tax

3,725,000

238,000

3,700,000

Long-term Debt, Fair Value

16,300,000,000

15,000,000,000

48,100,000

Maximum revolving loan commitments

3,500,000,000

2,500,000,000

Line of credit facility, optional additional commitments

750,000,000

Term Loan, optional additional commitments

500,000,000

Line of Credit Facility, Maximum Borrowing Capacity

2,750,000,000

2,000,000,000

Repayments of Lines of Credit

1,300,000,000

615,000,000

Long-term Line of Credit

1,980,000,000

400,000,000

Letters of Credit Outstanding, Amount

7,500,000

3,200,000

Debt Instrument, Term

5 years

Number of Annual Renewal Periods

Debt instrument, length of renewal period

1 year

Debt Instrument, Basis Spread on Variable Rate

1.25%

Maximum incremental term loan commitment

$1,000,000,000

Line of Credit Facility, Commitment Fee Percentage

0.15%

Ratio of total debt to EBITDA

7.25

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Narrative) (Details) (USD $)	Mar. 31, 2015
In Millions, unless otherwise specified	interest_rate_swap
South African Facility
Derivative [Line Items]
Number of interest rate swap agreements	15
Derivative, lower fixed interest rate range	6.09%
Derivative, higher fixed interest rate range	7.83%
2014 Colombian Long Term Credit Facility
Derivative [Line Items]
Derivative, fixed interest rate	5.74%
Designated as Hedging Instrument
Derivative [Line Items]
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net	0.8
Senior Notes \| Seven Point Zero Zero Percent Senior Notes
Derivative [Line Items]
Stated percentage interest rate	7.00%

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Schedule of Interest Rate Swap Agreements) (Details) (Interest Rate Swap)	Mar. 31, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2014	Mar. 31, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2014
In Thousands, unless otherwise specified	South African Facility	South African Facility	South African Facility	South African Facility	2014 Colombian Long Term Credit Facility	2014 Colombian Long Term Credit Facility	2014 Colombian Long Term Credit Facility	2014 Colombian Long Term Credit Facility
	USD ($)	ZAR	USD ($)	ZAR	USD ($)	COP	USD ($)	COP
Derivative [Line Items]
Notional	$35,524	430,978	$38,080	440,614	$38,334	98,750,000	$41,798	100,000,000
Derivative, Fair Value, Net	-14	-173	88	1,016
Fair Value, Gross Liability					($1,286)	-3,313,103	($647)	-1,548,688

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Schedule of Interest Rate Swap Agreements Impact on Other Comprehensive Income) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest rate swaps and treasury locks
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	($993)	($587)
Interest rate swaps and treasury locks
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	($411)	($969)

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	3 Months Ended
Fair Value Measurements (Narrative) (Details) (USD $)	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of Long-Lived Assets Held-for-use	$0		$0
Contingent consideration arrangements, low range of outcomes	0
Contingent consideration arrangements, high range of outcomes	38,377,000	[1]
Carrying value of long-term obligations, including current portion	15,700,000,000			14,600,000,000
Long-term Debt, Fair Value	16,300,000,000			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	9,200,000,000			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	$7,100,000,000			$5,300,000,000
Customer Concentration Risk \| Sales Revenue, Net
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Concentration risk	5.00%

[1]	The maximum potential value is based on current exchange rates. 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 $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	$14,394		$6,302
Acquisition-related contingent consideration	27,203	[1]	28,524		31,342	31,890
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments	14,394		6,302	[2]
Acquisition-related contingent consideration	27,203		28,524
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	14,394	[2]	6,302	[2]
Fair Value, Measurements, Recurring \| Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Acquisition-related contingent consideration	27,203		28,524
Fair Value, Measurements, Recurring \| Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		88
Derivative Liability	1,300		647
Fair Value, Measurements, Recurring \| Interest Rate Swap \| Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Asset	0		88
Derivative Liability	$1,300		$647

[1]	Estimate is determined using a probability weighted average of expected outcomes as of March 31, 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 $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at Beginning of Period	$28,524		$31,890
Additions	1,194		0
Settlements	-1,026		-615
Change in fair value	0		582
Foreign currency translation adjustment	-1,489		-515
Balance at End of Period	$27,203	[1]	$31,342

[1]	Estimate is determined using a probability weighted average of expected outcomes as of March 31, 2015.

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Loss (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	($794,221)	($311,220)
Other comprehensive loss before reclassifications, net of tax	-412,011	37,931
Amounts reclassified from accumulated other comprehensive loss, net of tax	372	879
Net current-period other comprehensive (loss) income	-411,639	38,810
Balance at end of period	-1,205,860	-272,410
Reclassification of unrealized losses on cash flow hedges to net income, tax	24	55
Unrealized Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	-1,345	-1,869
Other comprehensive loss before reclassifications, net of tax	-909	-780
Amounts reclassified from accumulated other comprehensive loss, net of tax	172	679
Net current-period other comprehensive (loss) income	-737	-101
Balance at end of period	-2,082	-1,970
Reclassification of unrealized losses on cash flow hedges to net income, tax	100	100
Treasury Lock
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	-2,231	-3,029
Other comprehensive loss before reclassifications, net of tax	0	0
Amounts reclassified from accumulated other comprehensive loss, net of tax	200	200
Net current-period other comprehensive (loss) income	200	200
Balance at end of period	-2,031	-2,829
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	-790,645	-306,322
Other comprehensive loss before reclassifications, net of tax	-411,102	38,711
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0
Net current-period other comprehensive (loss) income	-411,102	38,711
Balance at end of period	($1,201,747)	($267,611)

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details) (USD $)	3 Months Ended
Income Taxes (Narrative) (Details) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Unrecognized tax benefits that would impact effective tax rate	$30,800,000		$31,900,000
Impact of change in unrecognized tax benefit, lower	0
Impact of change in unrecognized tax benefits, upper	16,200,000
Penalties and tax-related interest expense during period	900,000	1,300,000
Unrecognized tax benefits, income tax penalties and interest accrued	$24,000,000		$24,900,000

StockBased_Compensation_Narrat

Stock-Based Compensation (Narrative) (Details) (USD $)	3 Months Ended
Stock-Based Compensation (Narrative) (Details) (USD $)	Mar. 31, 2015		Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$29,861,000		$24,604,000
Capitalized stock-based compensation expense	500,000		400,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	100,000
Shares granted, grant date fair value not yet established	46,756	[1]
Total unrecognized compensation expense	1,700,000
Total compensation cost not yet recognized, period for recognition	1 year
Three year performance grant, shares granted	70,135	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	23,379	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$94.57
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	49,100,000
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	$116,000,000
Total compensation cost not yet recognized, period for recognition	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	682,256
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	11,500,000
2007 Plan \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Minimum \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of potential target shares	0.00%
Maximum \| Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of potential target shares	200.00%

[1]	Represents the target number of shares issuable at the end of the three-year performance cycle based on performance in the first year.

StockBased_Compensation_Summar

Stock-Based Compensation (Summary of the Company's Option Activity) (Details) (Employee Stock Option)	3 Months Ended
	Mar. 31, 2015
Employee Stock Option
Options Activity, Outstanding [Roll Forward]
Outstanding at Beginning of Period	6,508,435
Granted	1,994,079
Exercised	-88,310
Forfeited	-38,911
Expired	-1,200
Outstanding at End of Period	8,374,093

StockBased_Compensation_Assump

Stock-Based Compensation (Assumptions Used to Determine the Grant Date Fair Value for Options Granted) (Details) (Employee Stock Option)	3 Months Ended
	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum range of risk-free interest rate	1.57%
Maximum range of risk-free interest rate	1.62%
Approximate risk-free interest rate	1.62%
Expected life of option grants	4 years 5 months 37 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%

StockBased_Compensation_Summar1

Stock-Based Compensation (Summary of the Company's Restricted Stock Unit Activity) (Details)	3 Months Ended
	Mar. 31, 2015
Restricted Stock Units
Restricted Stock Unit Activity, Outstanding [Roll Forward]
Outstanding at Beginning of Period	1,758,817
Granted	682,256
Vested	-651,253
Forfeited	-22,094
Outstanding at End of Period	1,767,726
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 based on performance in the first year.

Equity_Narrative_Details

Equity (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
Equity (Narrative) (Details) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Mar. 31, 2011	Mar. 05, 2015	Mar. 03, 2015	12-May-14
Class of Stock [Line Items]
Common stock, shares issued	425,883,631		399,508,751
Common stock, par value (in dollars per share)	$0.01		0.01
Proceeds from issuance of common stock	$2,440,390,000	$0
Issuance of preferred stock	1,338,009,000	0
Authorized repurchase of common stock				1,500,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	1,100,000,000
Proceeds from stock options	5,106,000	13,795,000
Accrued dividend, restricted stock units	3,000,000
Paid dividend, restricted stock units	1,200,000
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
Common Stock, Additional Shares Issued					2,350,000
Proceeds from issuance of common stock	2,440,390,000
Series B Preferred Stock
Class of Stock [Line Items]
Shares Issued, Price Per Share						$100
Preferred Stock, Dividend Rate, Percentage	5.50%		5.50%
Preferred stock, shares issued	1,375,000		0			12,500,000
Preferred Stock, Depositary Shares, Percentage of Preferred Shares						0.1
Preferred Stock, Par or Stated Value Per Share						$0.01
Preferred Stock, Additional Shares Issued					1,250,000
Issuance of preferred stock	$1,340,000,000
Preferred Stock, Liquidation Preference Per Share	$1,000
Preferred Stock, Liquidation Preference, Depositary Shares	100
Series A Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	5.25%		5.25%
Preferred stock, shares issued	6,000,000		6,000,000				6,000,000
Preferred Stock, Par or Stated Value Per Share	$0.01
Preferred Stock, Liquidation Preference Per Share	$100
Minimum \| Series B Preferred Stock
Class of Stock [Line Items]
Conversion Factor, Preferred Stock	8.5911
Minimum \| Series A Preferred Stock
Class of Stock [Line Items]
Conversion Factor, Preferred Stock	0.9174
Maximum \| Series B Preferred Stock
Class of Stock [Line Items]
Conversion Factor, Preferred Stock	10.3093
Maximum \| Series A Preferred Stock
Class of Stock [Line Items]
Conversion Factor, Preferred Stock	1.1468

Equity_Schedule_Of_Dividends_D

Equity (Schedule Of Dividends) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Dividends Payable [Line Items]
Distribution per share, common stock (in dollars per share)	$0.42	$0.32
Aggregate Payment Amount, Common Stock	$152,037	$554
Aggregate Payment Amount, Preferred Stock	7,875	0
Common Stock \| Fourth Quarter
Dividends Payable [Line Items]
Distribution per share, common stock (in dollars per share)	$0.38
Aggregate Payment Amount, Common Stock	150,700
Common Stock \| First Quarter
Dividends Payable [Line Items]
Distribution per share, common stock (in dollars per share)	$0.42
Aggregate Payment Amount, Common Stock	177,700
Series A Preferred Stock \| First Quarter
Dividends Payable [Line Items]
Preferred Stock, Dividends Per Share, Declared	$1.31
Aggregate Payment Amount, Preferred Stock	$7,900

Earnings_Per_Share_Schedule_of

Earnings Per Share (Schedule of Earnings Per Basic And Diluted by Common Class) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net income attributable to American Tower Corporation stockholders	$193,317	$202,499
Dividends on preferred stock	-9,819	0
NET INCOME ATTRIBUTABLE TO AMERICAN TOWER CORPORATION COMMON STOCKHOLDERS	$183,498	$202,499
Basic weighted average common shares outstanding (in shares)	405,111	395,146
Dilutive securities (in shares)	4,288	3,974
Diluted weighted average common shares outstanding (in shares)	409,399	399,120
Basic net income attributable to American Tower Corporation common stockholders per common share (in dollars per share)	$0.45	$0.51
Diluted net income attributable to American Tower Corporation common stockholders per common share (in dollars per share)	$0.45	$0.51

Earnings_Per_Share_Earnings_Pe

Earnings Per Share Earnings Per Share (Shares Excluded From Dilutive Effect) (Details)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 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	3	0
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	501	1,708
Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	9,194	0

Commitments_And_Contingencies_

Commitments And Contingencies (Narrative) (Details)	0 Months Ended		3 Months Ended	1 Months Ended	3 Months Ended
	Jan. 21, 2014	Jan. 21, 2014	Mar. 31, 2015	Dec. 31, 2000	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2015
	USD ($)	INR	At T Transaction	ALLTEL Transaction	ALLTEL Transaction	Verizon Transaction	Commitments prior to June 30, 2020	Commitments subsequent to June 30, 2020
			USD ($)	USD ($)	USD ($)	USD ($)	At T Transaction	At T Transaction
			renewal_periods	towers		renewal_periods
			towers			sites
Long-term Purchase Commitment [Line Items]
Operating Leases, Future Minimum Payments Receivable						$3,000,000,000
Operating lease, future minimum rental receipts, average recognition period						10 years
Operating Leases, Future Minimum Payments Due						2,200,000,000
Operating lease, future minimum rental payments, average recognition period						17 years
Right to lease, weighted average term						28 years
Lessee leasing arrangements, operating leases, term of contract			27 years
Number of sites acquired			31
Customer Lease Initial Term						10 years
Aggregate purchase option price for towers			659,400,000		73,700,000	5,000,000,000
Purchase price accretion rate (per year)			10.00%	3.00%
Successive Terms To Renew Lease			4			8
Lessee Leasing Arrangements, Operating Leases, Renewal Term						5 years	5 years	1 year
Long-term purchase commitment, time period				15 years
Capital Leased Assets, Number of Units			2,400	1,800		11,285
Cash purchase price per tower				27,500
Purchase price of tower in shares of common stock					769
Value of potential shares payable					128,200,000
India Tax Assessment	$369,000,000	22,600,000,000

Acquisitions_and_Other_Transac2

Acquisitions and Other Transactions (Narrative) (Details) (USD $)

3 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Mar. 27, 2015

Nov. 20, 2014

Dec. 31, 2014

Apr. 04, 2014

Nov. 24, 2014

Nov. 21, 2014

Dec. 31, 2013

Nov. 19, 2014

Apr. 03, 2014

site

towers

sites

propertyinterests

Business Acquisition [Line Items]

Pro forma information, revenue of acquiree since acquisition date, actual

$4,500,000

Pro forma information gross margin of acquiree since acquisition date actual

2,100,000

Acquisition and merger related expenses

3,000,000

9,800,000

Integration related costs

1,800,000

2,500,000

Aggregate purchase price

568,890,000

Acquisition-related contingent consideration

27,203,000

[1]

31,342,000

28,524,000

31,890,000

Value added tax and other consumption tax receivables

21,920,000

23,228,000

[2]

Estimated useful lives

11 years

Contingent Consideration, Settlements

-1,026,000

Verizon Transaction

Business Acquisition [Line Items]

Number of sites acquired

11,448

Aggregate purchase price

5,053,000,000

Business Acquisition, Transaction Costs

9,900,000

Other International Acquisitions 2015

Business Acquisition [Line Items]

Number of sites acquired

Aggregate purchase price

500,000

Other Us Acquisition 2015

Business Acquisition [Line Items]

Number of sites acquired

190

Aggregate purchase price

121,300,000

Number of property interests acquired

Acquisition-related contingent consideration

1,200,000

BR Towers

Business Acquisition [Line Items]

Number of sites acquired

2,504

Aggregate purchase price

568,900,000

Number of property interests acquired

Additional Sites To Be Acquired

2,113

Right to use, property interests acquired

Payments for Repurchase of Trust Preferred Securities

61,100,000

Assumption of existing indebtedness at historical cost

261,100,000

Repayments of Assumed Debt

13,500,000

135,600,000

Noncash or Part Noncash Acquisition, Value of Liabilities Assumed, Current Portion

11,500,000

Richland Acquisition

Business Acquisition [Line Items]

Number of sites acquired

Aggregate purchase price

188,900,000

189,400,000

Number of property interests acquired

Assumption of existing indebtedness at historical cost

196,500,000

Liabilities, Fair Value Adjustment

5,500,000

Other International Acquisitions 2014

Business Acquisition [Line Items]

Number of sites acquired

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

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

184

Aggregate purchase price

180,800,000

Number of property interests acquired

Acquisition-related contingent consideration

6,300,000

Contingent Consideration, Settlements

100,000

Airtel Acquisition

Business Acquisition [Line Items]

Aggregate purchase price

1,100,000,000

Maximum number of communications sites to be acquired

4,800

Preliminary Purchase Price Allocation | Other International Acquisitions 2015

Business Acquisition [Line Items]

Aggregate purchase price

491,000

Assumption of existing indebtedness at historical cost

Preliminary Purchase Price Allocation | Other Us Acquisition 2015

Business Acquisition [Line Items]

Aggregate purchase price

121,298,000

Assumption of existing indebtedness at historical cost

Preliminary Purchase Price Allocation | BR Towers

Business Acquisition [Line Items]

Aggregate purchase price

568,890,000

Assumption of existing indebtedness at historical cost

261,136,000

[3]

261,136,000

[3]

Preliminary Purchase Price Allocation | Richland Acquisition

Business Acquisition [Line Items]

Aggregate purchase price

189,379,000

Assumption of existing indebtedness at historical cost

201,999,000

[3]

201,999,000

[3]

Preliminary Purchase Price Allocation | Other US Acquisition 2014

Business Acquisition [Line Items]

Aggregate purchase price

180,822,000

Assumption of existing indebtedness at historical cost

Maximum | Preliminary Purchase Price Allocation

Business Acquisition [Line Items]

Acquired finite-live intangible assets, weighted average useful life

20 years

Leased Sites | Verizon Transaction

Business Acquisition [Line Items]

Aggregate purchase price

4,964,000,000

Capital Leased Assets, Number of Units

11,285

Right to lease, weighted average term

28 years

Initial Lease Term

10 years

Successive Terms To Renew Lease

Lessee Leasing Arrangements, Operating Leases, Renewal Term

5 years

Future monthly sublease rent per tower

1,900

Fixed annual rent escalation percentage

2.00%

Owned Sites | Verizon Transaction

Business Acquisition [Line Items]

Number of sites acquired

163

Aggregate purchase price

$99,000,000

First portfolio | TIM Acquisition

Business Acquisition [Line Items]

Maximum number of communications sites to be acquired

5,240

Second portfolio | TIM Acquisition

Business Acquisition [Line Items]

Maximum number of communications sites to be acquired

1,240

[1]

Estimate is determined using a probability weighted average of expected outcomes as of March 31, 2015.

[2]

DecemberÂ 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 Richlandâ€™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_Transac3

Acquisitions and Other Transactions (Schedule of Aggregate Purchase Consideration Paid and the Amount of Assets Acquired) (Details) (USD $)	3 Months Ended		0 Months Ended	12 Months Ended		0 Months Ended
	Mar. 31, 2015		Mar. 27, 2015	Dec. 31, 2014		Nov. 20, 2014	Apr. 04, 2014
Intangible assets:
Goodwill	$3,980,174,000			$4,028,549,000	[1]
Aggregate purchase price	568,890,000
Verizon Transaction
Business Acquisition [Line Items]
Transaction costs paid	4,700,000
Intangible assets:
Aggregate purchase price			5,053,000,000
Other US Acquisition 2014
Intangible assets:
Fair value of net assets acquired	180,822,000
Net assets acquired	164,998,000			164,998,000
Aggregate purchase price				180,800,000
Other US Acquisition 2014 \| Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	797,000			797,000
Non-current assets	0			0
Property and equipment	38,413,000			38,413,000
Intangible assets:
Customer-related intangible assets	89,990,000			89,990,000
Current liabilities	-1,997,000			-1,997,000
Other non-current liabilities	-1,675,000			-1,675,000
Goodwill	15,824,000			15,824,000	[2]
Net assets acquired				180,822,000
Assumption of existing indebtedness at historical cost	0			0
Aggregate purchase price	180,822,000			180,822,000
Other US Acquisition 2014 \| Preliminary Purchase Price Allocation \| Acquired Network Location
Intangible assets:
Network location intangible assets	39,470,000			39,470,000
Other Intangible Assets, Net				0
BR Towers
Intangible assets:
Fair value of net assets acquired	891,082,000
Net assets acquired	726,365,000			-726,127,000
Assumption of existing indebtedness at historical cost						-261,100,000
Preferred stock outstanding	-61,056,000
Aggregate purchase price						568,900,000
BR Towers \| Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	32,070,000			31,832,000
Non-current assets	9,135,000			9,135,000
Property and equipment	141,422,000			141,422,000
Intangible assets:
Customer-related intangible assets	495,279,000			495,279,000
Current liabilities	-23,930,000			-23,930,000
Other non-current liabilities	-101,508,000			-101,508,000
Goodwill	164,717,000	[2]		164,955,000	[2]
Net assets acquired				891,082,000
Assumption of existing indebtedness at historical cost	-261,136,000	[3]		-261,136,000	[3]
Preferred stock outstanding				-61,056,000
Aggregate purchase price				568,890,000
BR Towers \| Preliminary Purchase Price Allocation \| Acquired Network Location
Intangible assets:
Network location intangible assets	136,233,000	[4]		136,233,000	[4]
Other Intangible Assets, Net	37,664,000	[4]		37,664,000	[4]
Richland Acquisition
Intangible assets:
Fair value of net assets acquired	390,917,000	[5]
Net assets acquired	346,789,000	[5]		358,955,000
Assumption of existing indebtedness at historical cost	-196,500,000						-196,500,000
Aggregate purchase price	188,900,000						189,400,000
Richland Acquisition \| Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets				8,583,000
Non-current assets				0
Property and equipment				185,777,000
Intangible assets:
Customer-related intangible assets				169,452,000
Current liabilities				-3,635,000
Other non-current liabilities				-2,922,000
Goodwill				32,423,000	[2]
Net assets acquired				391,378,000
Assumption of existing indebtedness at historical cost	-201,999,000	[3]		-201,999,000	[3]
Aggregate purchase price				189,379,000
Richland Acquisition \| Preliminary Purchase Price Allocation \| Acquired Network Location
Intangible assets:
Network location intangible assets				1,700,000
Other Intangible Assets, Net				0
Richland Acquisition \| Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	8,583,000
Non-current assets	0
Property and equipment	154,899,000
Intangible assets:
Customer-related intangible assets	186,455,000
Current liabilities	-3,635,000
Other non-current liabilities	-2,922,000
Goodwill	44,128,000
Aggregate purchase price	188,918,000	[5]
Richland Acquisition \| Purchase Price Allocation \| Acquired Network Location
Intangible assets:
Network location intangible assets	3,409,000
Other International Acquisitions 2015
Intangible assets:
Aggregate purchase price	500,000
Other International Acquisitions 2015 \| Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	0
Non-current assets	0
Property and equipment	504,000
Intangible assets:
Customer-related intangible assets	0	[6]
Network location intangible assets	0	[6]
Current liabilities	0
Other non-current liabilities	-13,000
Goodwill	0	[7]
Fair value of net assets acquired	491,000
Net assets acquired	491,000
Assumption of existing indebtedness at historical cost	0
Aggregate purchase price	491,000
Other Us Acquisition 2015
Intangible assets:
Aggregate purchase price	121,300,000
Other Us Acquisition 2015 \| Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	164,000
Non-current assets	1,000,000
Property and equipment	29,730,000
Intangible assets:
Customer-related intangible assets	48,190,000	[6]
Network location intangible assets	34,850,000	[6]
Current liabilities	-238,000
Other non-current liabilities	-1,946,000
Goodwill	9,548,000	[7]
Fair value of net assets acquired	121,298,000
Net assets acquired	111,750,000
Assumption of existing indebtedness at historical cost	0
Aggregate purchase price	121,298,000
Leased Sites \| Verizon Transaction
Intangible assets:
Aggregate purchase price			4,964,000,000
Leased Sites \| Verizon Transaction \| Preliminary Purchase Price Allocation
Business Acquisition [Line Items]
Current assets	13,112,000
Non-current assets	208,492,000
Property and equipment	2,031,657,000
Intangible assets:
Customer-related intangible assets	1,742,824,000	[7]
Network location intangible assets	1,179,409,000	[7]
Current liabilities	-10,747,000
Other non-current liabilities	-200,530,000	[8]
Fair value of net assets acquired	$4,964,217,000	[9]

[1]	Balances have been revised to reflect purchase accounting measurement period adjustments.
[2]	Goodwill was allocated to the Companyâ€™s domestic and international rental and management segments, as applicable, 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. Assumed Richland debt included $196.5 million of Richlandâ€™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.
[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]	The allocation of the purchase price was finalized during the three months ended March 31, 2015.
[6]	Customer-related intangible assets and network location intangible assets are amortized on a straight-line basis over periods of up to 20 years.
[7]	Goodwill was allocated to the Companyâ€™s domestic rental and management segment and the Company expects goodwill recorded will be deductible for tax purposes.
[8]	Represents liabilities recorded for asset retirement obligations.
[9]	Includes approximately $9.9 million of transaction costs, which have been capitalized as part of the assetsâ€™ fair value, $4.7 million of which was paid during the three months ended March 31, 2015.

Acquisitions_and_Other_Transac4

Acquisitions and Other Transactions (Pro Forma Information) (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Business Acquisition, Pro Forma Information [Abstract]
Operating revenues	$1,170,772	$1,115,001
Net income attributable to American Tower Corporation	$145,137	$147,760
Basic earnings per share (in dollars per share)	$0.34	$0.35
Diluted earnings per share (in dollars per share)	$0.34	$0.35

Acquisitions_and_Other_Transac5

Acquisitions and Other Transactions (Schedule of Contingent Consideration) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, low range of outcomes	$0
Contingent consideration arrangements, high range of outcomes	38,377,000	[1]
Acquisition-related contingent consideration	27,203,000	[2]	28,524,000	31,342,000	31,890,000
Asset additions during period	1,194,000	[3]
Contingent Consideration, Settlements	-1,026,000
COLOMBIA
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	27,440,000	[1]
Acquisition-related contingent consideration	18,328,000	[2]
COSTA RICA
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	3,960,000	[1]
Acquisition-related contingent consideration	1,898,000	[2]
GHANA
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	470,000	[1]
Acquisition-related contingent consideration	470,000	[2]
UNITED STATES
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration arrangements, high range of outcomes	6,507,000	[1]
Acquisition-related contingent consideration	6,507,000	[2]
Asset additions during period	1,194,000	[3]
Contingent Consideration, Settlements	($1,026,000)

[1]	The maximum potential value is based on current exchange rates. The minimum value could be zero.
[2]	Estimate is determined using a probability weighted average of expected outcomes as of March 31, 2015.
[3]	Based on preliminary acquisition accounting upon closing of certain acquisitions during three months ended March 31, 2015.

Business_Segments_Narrative_De

Business Segments (Narrative) (Details)	3 Months Ended
	Mar. 31, 2015
	segment
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 $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment revenues	$1,079,190		$984,089
Segment operating expenses	264,069	[1]	260,265	[2]
Interest income, TV Azteca, net	2,596		2,595
Segment gross margin	817,717		726,419
Segment selling, general, administrative and development expense	64,869	[1]	59,155	[2]
Segment operating profit	752,848		667,264
Stock-based compensation expense	29,861		24,604
Other selling, general, administrative and development expense	29,131		26,774
Depreciation, amortization and accretion	263,520		245,763
Other expense (principally interest expense and other expenses)	210,972		159,161
INCOME FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	219,364		210,962
Total assets	25,930,194		20,417,407		21,331,545
Operating Segments \| Rental And Management
Segment Reporting Information [Line Items]
Segment revenues	1,062,180		960,120
Segment operating expenses	258,825	[1]	250,463	[2]
Segment gross margin	805,951		712,252
Segment selling, general, administrative and development expense	61,433	[1]	56,625	[2]
Segment operating profit	744,518		655,627
Total assets	25,772,402		20,150,407
Operating Segments \| Rental And Management \| Domestic
Segment Reporting Information [Line Items]
Segment revenues	717,880		635,779
Segment operating expenses	133,032	[1]	121,509	[2]
Interest income, TV Azteca, net	0		0
Segment gross margin	584,848		514,270
Segment selling, general, administrative and development expense	26,822	[1]	27,409	[2]
Segment operating profit	558,026		486,861
Total assets	19,560,579		13,527,578
Operating Segments \| Rental And Management \| International
Segment Reporting Information [Line Items]
Segment revenues	344,300		324,341
Segment operating expenses	125,793	[1]	128,954	[2]
Segment gross margin	221,103		197,982
Segment selling, general, administrative and development expense	34,611	[1]	29,216	[2]
Segment operating profit	186,492		168,766
Total assets	6,211,823		6,622,829
Operating Segments \| Network Development Services
Segment Reporting Information [Line Items]
Segment revenues	17,010		23,969
Segment operating expenses	5,244	[1]	9,802	[2]
Interest income, TV Azteca, net	0		0
Segment gross margin	11,766		14,167
Segment selling, general, administrative and development expense	3,436	[1]	2,530	[2]
Segment operating profit	8,330		11,637
Total assets	67,226		65,417
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Stock-based compensation expense	29,861		24,604
Other selling, general, administrative and development expense	29,131		26,774
Depreciation, amortization and accretion	263,520		245,763
Other expense (principally interest expense and other expenses)	210,972		159,161
Total assets	90,566		201,583
TV Azteca
Segment Reporting Information [Line Items]
Interest income, TV Azteca, net	2,596		2,595
TV Azteca \| Operating Segments \| Rental And Management
Segment Reporting Information [Line Items]
Interest income, TV Azteca, net	2,596		2,595
TV Azteca \| Operating Segments \| Rental And Management \| International
Segment Reporting Information [Line Items]
Interest income, TV Azteca, net	2,596		2,595
Operating Expense \| Corporate, Non-Segment
Segment Reporting Information [Line Items]
Stock-based compensation expense	600		500
Selling General Administrative And Development Expense
Segment Reporting Information [Line Items]
Stock-based compensation expense	29,290		24,100
Selling General Administrative And Development Expense \| Corporate, Non-Segment
Segment Reporting Information [Line Items]
Stock-based compensation expense	$29,300		$24,100

[1]	Segment operating expenses and segment selling, general, administrative and development expenses exclude stock-based compensation expense of $0.6 million and $29.3 million, respectively.
[2]	Segment operating expenses and segment selling, general, administrative and development expenses exclude stock-based compensation expense of $0.5 million and $24.1 million, respectively.

Subsequent_Events_Subsequent_E

Subsequent Events Subsequent Events (Narrative) (Details)	3 Months Ended			0 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Apr. 29, 2015	Apr. 29, 2015	Apr. 29, 2015	Apr. 29, 2015	Apr. 29, 2015
	USD ($)	USD ($)	Seven Point Zero Zero Percent Senior Notes	Seven Point Zero Zero Percent Senior Notes	Seven Point Zero Zero Percent Senior Notes	TIM Acquisition	TIM Acquisition	TIM Acquisition
			Senior Notes	Senior Notes	Senior Notes	Subsequent Event	Subsequent Event	Subsequent Event
				Subsequent Event	Subsequent Event	USD ($)	BRL	BRL
				USD ($)				sites
Subsequent Event [Line Items]
Stated percentage interest rate			7.00%		7.00%
Debt, amount of principal redemption percentage					114.06%
Repayments of Senior Debt				$571,700,000
Cash paid for interest	199,022,000	154,497,000		1,400,000
Loss on retirement of long-term obligations	-3,725,000	-238,000		74,300,000
Number of sites acquired								4,176
Aggregate purchase price	568,890,000					644,300,000	1,900,000,000
Letters of Credit Outstanding, Amount								92,100,000