CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 90,908	$ 105,931	$ 5,035
Other comprehensive loss, net of applicable taxes:
Foreign currency translation adjustment	(3,347)	(3,018)	(3,585)
Less: reclassification adjustment for translation gain included in other income	0	280	0
Foreign currency translation adjustment, net	(3,347)	(2,738)	(3,585)
Unrealized gain (loss) on short-term investments	12	(27)	53
Total other comprehensive loss	(3,335)	(2,765)	(3,532)
Comprehensive income	$ 87,573	$ 103,166	$ 1,503