CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 150,668	$ 218,806	$ 128,687
Other comprehensive loss, net of tax:
Foreign currency translation adjustment	(8,902)	(1,626)	(15,471)
Change in fair value on available-for-sale investments, net of tax expense (benefit) of $181, $149 and $(460) for the years ended December 31, 2020, 2019 and 2018, respectively	558	1,143	(1,418)
Other comprehensive loss, net of tax	(8,344)	(483)	(16,889)
Comprehensive income	$ 142,324	$ 218,323	$ 111,798