Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Condensed Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 40,591	$ 45,846	$ 70,585	$ 69,956
Other comprehensive income (loss), net of income tax:
Foreign currency translation adjustment	(4,795)	5,212	7,400	(23,086)
Total comprehensive income	35,796	51,058	77,985	46,870
Total comprehensive income attributable to:
Stockholders	34,914	50,295	76,348	45,960
Non-controlling interests	$ 882	$ 763	$ 1,637	$ 910