Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 109,242	$ 113,981
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(13,075)	3,397
Unrealized gain (loss) on investments:
Unrealized gains (losses) during the period, net of income taxes of $(339) and $(240)	1,131	797
Less: reclassification adjustment for losses (gains) realized in net income, net of income taxes of $(28) and $(24)	100	86
Unrealized gain (loss) on investments:	1,231	883
Total other comprehensive (loss) income, net of tax	(11,844)	4,280
Comprehensive income	$ 97,398	$ 118,261