CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Income and Comprehensive Income [Abstract]
Net income	$ 594,025	$ 381,840	$ 373,606
Net change in fair value of cash flow hedges, net of taxes of $905, $1,334 and $6,046, respectively	(5,315)	1,977	9,496
Reclassification of unrealized losses on cash flow hedges to net income, net of taxes of $208, $74 and $75, respectively	1,132	225	118
Net unrealized (loss) gain on available-for-sale securities, net of taxes of $0, $65 and $4, respectively	0	(104)	7
Reclassification of unrealized losses on available-for-sale securities to net income	495	0	0
Foreign currency translation adjustments, net of taxes of $7,677, $1,702 and $3,541, respectively	(58,387)	(187,466)	41,081
Reclassifications due to REIT Conversion	0	(1,752)	0
Other comprehensive (loss) income	(62,075)	(187,120)	50,702
Comprehensive income	531,950	194,720	424,308
Comprehensive loss (income) attributable to non-controlling interest	64,603	21,072	(670)
Comprehensive income attributable to American Tower Corporation	$ 596,553	$ 215,792	$ 423,638