Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Premiums Written, Net [Abstract]
Direct written premiums	$ 63,847	$ 52,862
Assumed written premiums	0	0
Ceded written premiums	(8,756)	(8,700)
Net written premiums	55,091	44,162
Premiums Earned, Net [Abstract]
Direct earned premiums	56,593	48,462
Assumed earned premiums	0	0
Ceded earned premiums	(8,532)	(8,029)
Net earned premiums	48,061	40,433
Ceded incurred losses and loss adjustment expenses	2,900	$ 2,400
Reinsurance recoverables on paid losses	1,000		$ 1,400
Reinsurance recoverables on unpaid losses	$ 49,700		$ 48,200