Deferred Policy Acquisition Costs - Activity in Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance at beginning of period	$ 12,050	$ 12,956	$ 12,781	$ 13,290
Deferred policy acquisition costs	6,443	6,121	12,225	12,259
Amortization of policy acquisition costs	(6,472)	(6,428)	(12,985)	(12,900)
Net change	(29)	(307)	(760)	(641)
Balance at end of period	$ 12,021	$ 12,649	$ 12,021	$ 12,649