Other Real Estate Owned - Activity in Other Real Estate Owned (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Regulatory Assets [Abstract]
Balance at beginning of period	$ 3,232	$ 8,810	$ 18,546
Additions	1,192	2,025	4,016
Sales	(2,077)	(6,689)	(11,160)
Impairments	(178)	(914)	(2,592)
Balance at end of period	$ 2,169	$ 3,232	$ 8,810