CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statement Of Comprehensive Income [Abstract]
Net income	$ 45,096	$ 32,909	$ 36,952
Other comprehensive income (loss):
Change in net unrealized gains (losses) on investments, net of tax	136	(89)	(37)
Change in currency translation adjustments	(194)	1,663	(119)
Total comprehensive income	$ 45,038	$ 34,483	$ 36,796