Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 54,002	$ 38,594	$ 154,629	$ 127,021
Net cumulative translation adjustment and foreign currency exchange hedge, net of tax of $1,012, $240, $1,281 and $746, respectively	(1,416)	(582)	(1,398)	(1,602)
Net unrealized gain (loss) on securities available-for-sale, net of tax of $22, $23, $309 and $(66), respectively	70	72	988	(205)
Comprehensive income	$ 52,656	$ 38,084	$ 154,219	$ 125,214