Foreclosed Assets - Summary of Activity in Balance of Foreclosed Assets (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) Assets	Dec. 31, 2017 USD ($) Assets	Dec. 31, 2016 USD ($)
Repossessed Assets [Abstract]
Beginning balance, net	$ 3,226	$ 3,986
Additions/transfers from loans	1,262	1,563
Dispositions/sales	(2,119)	(2,161)
Valuation adjustments	(89)	(162)
Ending balance, net	2,280	3,226	$ 3,986
Ending valuation allowance	$ (116)	$ (200)
Ending number of foreclosed assets | Assets	11	16
Proceeds from sale of foreclosed assets	$ 2,527	$ 2,872	4,010
Gain on sale of foreclosed assets	$ 408	$ 711	$ 262