Reinsurance, Effects of Reinsurance on Premiums Written and Earned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Written [Abstract]
Direct	$ 223,191	$ 188,440	$ 176,865
Assumed	0	38	144
Ceded	(33,719)	(21,214)	(92,991)
Net written premiums	189,472	167,264	84,018
Earned [Abstract]
Direct	209,426	180,794	170,401
Assumed	0	53	148
Ceded	(33,373)	(47,031)	(96,227)
Net earned premiums	176,053	133,816	74,322
Ceded incurred losses and loss adjustment expenses	$ 12,200	$ 13,700	$ 41,200