Unaudited Condensed Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net income	$ 27,394	$ 41,797	$ 120,552	$ 127,751
Foreign currency translation adjustments	7,497	13,513	(9,773)	10,991
Comprehensive income	34,891	55,310	110,779	138,742
Comprehensive income (loss) attributable to noncontrolling interests	(620)	(745)	(2,532)	(1,600)
Comprehensive income attributable to common stockholders	$ 34,271	$ 54,565	$ 108,247	$ 137,142