Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 133,778	$ 101,066	$ 263,248	$ 210,308
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	994	940	2,679	(12,136)
Unrealized (loss) gain on investments:
Unrealized (losses) gains during the period, net of income taxes of $85, $(33), $245 and $(372)	(292)	113	(835)	1,244
Reclassification adjustment for losses realized in net income, net of income taxes of $(49), $(35), $(123) and $(63)	179	116	432	217
Total other comprehensive income (loss), net of tax	881	1,169	2,276	(10,675)
Comprehensive income	$ 134,659	$ 102,235	$ 265,524	$ 199,633