Income Taxes - Summary of Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 13,380	$ 24,208
Stock-based compensation	164	404
Unearned premiums and loss and loss adjustment expense reserves	5,408	6,752
Goodwill and identifiable intangible assets	853	2,832
Alternative minimum tax (“AMT”) credit carryforwards	1,991	2,015
Accrued expenses and other nondeductible items	1,292	1,345
Other	2,434	3,619
Deferred Tax Assets, Gross, Total	25,522	41,175
Deferred tax liabilities:
Deferred acquisition costs	(1,039)	(1,698)
Identifiable intangible assets	(1,200)	(1,872)
Loss reserve discounting	(1,206)
Other	(191)	(92)
Deferred tax liabilities, gross	(3,636)	(3,662)
Total net deferred tax asset	21,886	37,513
Less: Valuation allowance	(1,337)	(1,872)
Net deferred tax asset	$ 20,549	$ 35,641