UNAUDITED 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
Statement of Comprehensive Income [Abstract]
Net income	$ 10,960	$ 16,692	$ 80,351	$ 52,601
Other comprehensive income:
Unrealized gains (losses) on marketable securities, net of tax	101	(2)	527	415
Comprehensive income	$ 11,061	$ 16,690	$ 80,878	$ 53,016