Deferred Policy Acquisition Costs - Activity in Deferred Policy Acquisition Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance at beginning of period	$ 12,649	$ 13,182	$ 13,290	$ 12,102
Deferred policy acquisition costs	6,759	6,287	19,018	19,383
Amortization of policy acquisition costs	(6,655)	(6,266)	(19,555)	(18,282)
Net change	104	21	(537)	1,101
Balance at end of period	$ 12,753	$ 13,203	$ 12,753	$ 13,203