Income Taxes - Provision for Income Taxes Differs from Amounts Computed by Applying Statutory Federal Corporate Tax Rate (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Tax Disclosure [Abstract]
Provision for income taxes at statutory rate	$ 242	$ 1,303	$ 523	$ 1,495
Tax effect of:
Tax-exempt investment income	(5)	(5)	(10)	(10)
Change in the beginning of the period balance of the valuation allowance for deferred tax assets allocated to federal income taxes	2	(1,233)	2	(1,456)
Stock-based compensation	22	7	22	44
State income taxes, net of federal income tax benefit and state valuation allowance	122	175	158	201
Other	(8)	7	(2)	16
Income tax expense	$ 375	$ 254	$ 693	$ 290