Deferred Policy Acquisition Costs - Activity in Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance at beginning of period	$ 12,781	$ 13,290
Deferred policy acquisition costs	5,782	6,138
Amortization of policy acquisition costs	(6,513)	(6,472)
Net change	(731)	(334)
Balance at end of period	$ 12,050	$ 12,956