Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 17,090	$ 11,510	$ 12,536	$ 8,103
Unrealized (losses) gains on investments, net of tax	2,151	6,877	(3,099)	4,142
Comprehensive income	$ 19,241	$ 18,387	$ 9,437	$ 12,245