Other Real Estate Owned - Activity in Other Real Estate Owned (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Regulatory Assets [Abstract]
Balance at beginning of period	$ 2,819	$ 3,729	$ 3,232	$ 8,810
Additions	411	474	1,084	1,649
Sales	(271)	(511)	(1,248)	(6,136)
Impairments	(18)	(129)	(127)	(760)
Balance at end of period	$ 2,941	$ 3,563	$ 2,941	$ 3,563