Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 129,470	$ 109,242
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	1,685	(13,075)
Unrealized (loss) gain on investments:
Unrealized (losses) gains during the period, net of income taxes of $160 and $(339)	(543)	1,131
Reclassification adjustment for losses realized in net income, net of income taxes of $(74) and $(28)	253	100
Unrealized (loss) gain on investments	(290)	1,231
Total other comprehensive income (loss), net of tax	1,395	(11,844)
Comprehensive income	$ 130,865	$ 97,398