Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 30,918	$ 22,715	$ 93,007	$ 71,546
Net cumulative translation adjustment and foreign currency exchange hedge, net of tax of $346, $(69), $4,448 and $(229), respectively	(1,052)	(105)	(5,093)	(420)
Net unrealized gain (loss) on securities available-for-sale, net of tax of $(27), $(4), $109 and $(7), respectively	(44)	(6)	177	(12)
Comprehensive Income	$ 29,822	$ 22,604	$ 88,091	$ 71,114