Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Condensed Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 23,112	$ 10,323	$ 86,046	$ 38,469
Other comprehensive income (loss), net of income tax:
Foreign currency translation adjustment	3	6,009	(7,781)	22,822
Total comprehensive income	23,115	16,332	78,265	61,291
Total comprehensive income (loss) attributable to:
Stockholders	23,145	16,256	78,234	61,045
Non-controlling interests	$ (30)	$ 76	$ 31	$ 246