Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income	$ 65,203	$ 52,720	$ 35,172
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments, net of $0 tax in 2017, 2016 and 2015	6,369	(5,033)	(4,166)
Change in unrealized loss on available-for-sale securities, net of $0 tax in 2017, 2016 and 2015	(341)	(648)	(179)
Total other comprehensive income (loss), net of tax	6,028	(5,681)	(4,345)
Comprehensive income	$ 71,231	$ 47,039	$ 30,827