Other Real Estate Owned - Schedule of Activity in Other Real Estate Owned (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Real Estate Owned Disclosure Of Detailed Components [Abstract]
Balance, beginning of period	$ 725	$ 2,735
Transfers from non-acquired loans	3,795	950
Transfers from acquired loans	80	55
Other real estate sold	(528)	(2,961)
Write-downs	(7)	(54)
Balance, end of period	$ 4,065	$ 725