Other Real Estate Owned and Other Repossessed Assets - Expenses Related to Foreclosed and Repossessed Assets (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Other Real Estate And Foreclosed Assets [Abstract]
Net loss on sales	$ 12,000	$ 55,000
Provision for unrealized losses	19,000	23,000
Operating expenses, net of rental income	39,000	36,000
Total expenses	$ 70,000	$ 114,000