Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 138,045	$ 111,096	$ 401,293	$ 321,404
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(5,546)	7,085	(2,867)	(5,051)
Unrealized (loss) gain on investments:
Unrealized (losses) gains during the period, net of income taxes of $208, $154, $453 and $(218)	(713)	(542)	(1,548)	702
Reclassification adjustment for losses realized in net income, net of income taxes of $(67), $(63), $(190) and $(126)	238	238	670	455
Total other comprehensive (loss) income, net of tax	(6,021)	6,781	(3,745)	(3,894)
Comprehensive income	$ 132,024	$ 117,877	$ 397,548	$ 317,510