Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Condensed Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 17,713	$ 40,591	$ 28,146	$ 70,585
Other comprehensive income (loss), net of income tax:
Foreign currency translation adjustment	9,373	(4,795)	16,813	7,400
Total comprehensive income	27,086	35,796	44,959	77,985
Total comprehensive income attributable to:
Stockholders	26,976	34,914	44,789	76,348
Non-controlling interests	$ 110	$ 882	$ 170	$ 1,637