Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Premiums Written, Net [Abstract]
Premiums written - direct	$ 168,876	$ 124,036
Premiums written - assumed	0	0
Premiums written - ceded	(24,578)	(15,983)
Net written premiums	144,298	108,053
Premiums Earned, Net [Abstract]
Premiums earned - direct	145,031	103,734
Premiums earned - assumed	0	15
Premiums earned - ceded	(21,990)	(13,988)
Net earned premiums	123,041	89,761
Ceded incurred losses and loss adjustment expenses	12,501	6,452
Reinsurance recoverables on paid losses	1,372		$ 9,485
Reinsurance recoverable on unpaid losses	94,819	$ 69,099	83,730	$ 69,792
Reinsurance recoverables	$ 96,191		$ 93,215