Other Real Estate Owned and Other Repossessed Assets - Expenses Related to Foreclosed and Repossessed Assets (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Other Real Estate And Foreclosed Assets [Abstract]
Net loss on sales	$ 29,000	$ (4,000)	$ 57,000	$ 154,000
Provision for unrealized losses	26,000	49,000	62,000	82,000
Operating expenses, net of rental income	39,000	25,000	95,000	95,000
Total expenses	$ 94,000	$ 70,000	$ 214,000	$ 331,000