Reinsurance - Summary of Premiums Earned and Losses Incurred (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Premiums earned:
Direct	$ 287,223	$ 300,557	$ 876,541	$ 896,346
Assumed	2,660	2,729	7,551	8,719
Ceded	(35,039)	(47,173)	(122,664)	(144,489)
Net premiums earned	254,844	256,113	761,428	760,576
Losses incurred:
Direct	17,265	61,164	103,319	383,950
Assumed	(97)	229	(43)	528
Ceded	3,598	(20,707)	(13,710)	(65,462)
Losses incurred, net	$ 20,766	$ 40,686	$ 89,566	$ 319,016