Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Condensed Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 80,244	$ 98,582	$ 164,807	$ 277,742
Other comprehensive income (loss), net of income taxes:
Foreign currency translation adjustments	705	(631)	(81)	202
Unrealized gain on available-for-sale securities, net of income taxes	0	5	0	147
Other comprehensive income (loss), net of income taxes	705	(626)	(81)	349
Comprehensive income	$ 80,949	$ 97,956	$ 164,726	$ 278,091