Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Income Tax Examination [Line Items]
Unrecognized tax benefits	$ 0
Income tax examination	Federal and state tax returns for the 2012 through 2015 tax years are subject to examination
Amortization of low-income housing credit investments reflected as income tax expense	$ 390,000	$ 495,000
Tax benefits recorded as income tax expense	89,000
Carrying value of investment in affordable housing credits	$ 11,600,000		$ 12,000,000
Earliest Tax Year [Member]
Income Tax Examination [Line Items]
Income tax examination period	2012
Latest Tax Year [Member]
Income Tax Examination [Line Items]
Income tax examination period	2015
Tax Credit [Member]
Income Tax Examination [Line Items]
Affordable housing tax credits	$ 368,000