Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 52,522	$ 47,940
Net cumulative translation adjustment and foreign currency exchange hedge, net of tax of $(452) and $(823), respectively	1,118	268
Net unrealized gain (loss) on securities available-for-sale, net of tax of $143 and $(107), respectively	459	(334)
Comprehensive income	$ 54,099	$ 47,874