Other Real Estate Owned and Other Repossessed Assets - Real Estate Owned and Other Repossessed Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Other Real Estate And Foreclosed Assets [Abstract]
Real estate owned and other repossessed assets	$ 1,586		$ 2,789
Valuation allowance	(389)	$ (549)	(1,012)	$ (1,001)	$ (1,124)	$ (1,229)
End of period	$ 1,197		$ 1,777