Goodwill and Other Intangible Assets (Schedule of Other Intangible Assets) (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	$ 12,186	$ 12,688
Accumulated Amortization	(10,623)	(10,207)
Net Intangible Assets	1,563	2,481
Core Deposits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	9,300	9,300
Accumulated Amortization	(8,004)	(7,257)
Net Intangible Assets	1,296	2,043
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Intangible Assets	2,886	3,388
Accumulated Amortization	(2,619)	(2,950)
Net Intangible Assets	$ 267	$ 438