CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - UNAUDITED - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 21,504	$ 9,358
Other comprehensive loss, net of tax:
Foreign currency translation adjustments	(1,102)	(9,535)
Unrealized holding gains on short-term investments arising during period	911	3
Other comprehensive loss, net of tax	(191)	(9,532)
Total comprehensive income (loss), net of tax	$ 21,313	$ (174)