Foreclosed Assets - Summary of Expenses Related to Foreclosed Real Estate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate [Abstract]
Net gain on sale	$ (310)	$ (208)	$ (134)
Operating expenses, net of rental income	283	366	223
Total	$ (27)	$ 158	$ 89