Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Discounted unpaid losses and loss adjustment expenses	$ 1,026	$ 715
Unearned premiums	2,576	4,085
Net operating loss carryforwards	9,147	7,757
State net operating loss carryforwards	385	223
Other	135	203
Gross deferred tax assets	13,269	12,983
Less valuation allowance	(9,904)	(8,389)
Total deferred tax assets, net of allowance	3,365	4,594
Deferred tax liabilities:
Investment basis difference	19	45
Unrealized gains on investments	124	(156)
Deferred policy acquisition costs	2,684	4,519
Intangible assets	107	163
Property and equipment	85	202
Other	461	0
Total deferred tax liabilities	3,480	4,773
Net deferred tax liability	$ (115)	$ (179)