Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of period	$ 31,912	$ 23,564
Policy acquisition costs deferred:
Direct commissions deferred	24,650	18,078
Ceding commissions deferred	(6,204)	(3,872)
Other underwriting and policy acquisition costs	1,368	1,187
Policy acquisition costs deferred	19,814	15,393
Amortization of net policy acquisition costs	(16,985)	(12,952)
Balance, end of period	$ 34,741	$ 26,005