Unaudited Condensed Consolidated Statement of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net income	$ 34,435	$ 37,639	$ 93,158	$ 85,954
Foreign currency translation adjustments	(11,754)	(8,267)	(17,270)	(2,522)
Comprehensive income	22,681	29,372	75,888	83,432
Comprehensive income (loss) attributable to noncontrolling interests	(814)	(580)	(1,912)	(855)
Comprehensive income attributable to common stockholders	$ 21,867	$ 28,792	$ 73,976	$ 82,577