Other Real Estate Owned and Other Repossessed Assets - Real Estate Owned and Other Repossessed Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Other Real Estate And Foreclosed Assets [Abstract]
Real estate owned and other repossessed assets	$ 2,796		$ 3,956
Valuation allowance	(1,003)	$ (1,001)	(1,229)	$ (1,190)	$ (1,195)	$ (1,423)
End of period	$ 1,793		$ 2,727