CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - UNAUDITED - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 10,366	$ 19,379	$ 31,880	$ 38,630
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	2,671	(3,818)	(12,413)	29
Unrealized holding gains on short-term investments arising during period	52	10	28	28
Other comprehensive income (loss), net of tax	2,723	(3,808)	(12,385)	57
Total comprehensive income, net of tax	$ 13,089	$ 15,571	$ 19,495	$ 38,687