Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of period	$ 16,314	$ 12,768	$ 14,801	$ 11,775
Policy acquisition costs deferred:
Direct commissions deferred	13,880	10,298	26,243	19,675
Ceding commissions deferred	(3,258)	(2,609)	(6,514)	(5,150)
Other underwriting and policy acquisition costs	849	694	1,814	1,503
Policy acquisition costs deferred	11,471	8,383	21,543	16,028
Amortization of net policy acquisition costs	(9,133)	(7,028)	(17,692)	(13,680)
Balance, end of period	$ 18,652	$ 14,123	$ 18,652	$ 14,123