Earnings Per Common Share (Tables)

12 Months Ended

Dec. 31, 2012

Earnings Per Common Share

Schedule of earnings per basic and diluted by common class

		2012		2011		2010
Income from continuing operations attributable to American Tower Corporation		$	637,283	$	396,462	$	372,906
Basic weighted average common shares outstanding			394,772		395,711		401,152
Dilutive securities			4,515		4,484		2,920
Diluted weighted average common shares outstanding			399,287		400,195		404,072
Basic income from continuing operations attributable to
	American Tower Corporation per common share	$	1.61	$	1.00	$	0.93
Diluted income from continuing operations attributable to
	American Tower Corporation per common share	$	1.60	$	0.99	$	0.92