Investments - Additional Information (Detail) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Schedule Of Investments [Line Items]
Federal home loan bank stock	$ 6,500,000	$ 1,700,000
Federal reserve bank stock	6,100,000	6,100,000
Correspondent bank stock	468,000	468,000
Other equity investments	23,800,000	14,200,000
Other investments	17,110,000	12,681,000	[1]
FHLB [Member]
Schedule Of Investments [Line Items]
Securities pledged	18,000,000.0	23,100,000
Treasury Board Commonwealth of Virginia [Member]
Schedule Of Investments [Line Items]
Securities pledged	$ 0	$ 8,700,000

[1] Derived from audited December 31, 2021 Consolidated Financial Statements.