Income Taxes - Provision (Benefit) for Income Taxes Differs from Amounts Computed by Applying Statutory Federal Corporate Tax Rate (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes at statutory rate	$ (1,584)	$ 832	$ (1,061)	$ 2,327
Tax effect of:
Tax-exempt investment income	(5)	(5)	(15)	(16)
Change in the beginning of the period balance of the valuation allowance for deferred tax assets allocated to federal income taxes	6	(760)	8	(2,216)
Stock-based compensation		3	22	48
State income taxes, net of federal income tax benefit and state valuation allowance	(24)	177	134	378
Other	101	10	99	26
Income tax expense	$ (1,506)	$ 257	$ (813)	$ 547