Unaudited Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Unaudited Condensed Consolidated Statement of Comprehensive Income [Abstract]
Net income	$ 47,541	$ 47,927	$ 110,888	$ 162,484
Other comprehensive income:
Foreign currency translation adjustments	(5,018)	(28,182)	18,116	(42,941)
Total comprehensive income	42,523	19,745	129,004	119,543
Total comprehensive income attributable to noncontrolling interests	189	(464)	(102)	(1,038)
Total comprehensive income attributable to common stockholders	$ 42,712	$ 19,281	$ 128,902	$ 118,505