Organization, Basis of Presentation and Recent Accounting Pronouncements - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Sep. 15, 2020
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Common stock, shares authorized	10,000,000	10,000,000
Common stock, par value	$ 4.00	$ 4.00
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, par value	$ 1.00	$ 1.00	$ 1.00
Preferred stock, shares outstanding	28,750	28,750
Investment securities held-to-maturity, at amortized cost	$ 20,349,000	$ 22,520,000
Federal reserve bank stock percentage	6.00%
Minimum required percentage of Federal Reserve Bank stock to be maintained of outstanding borrowings	4.50%
Minimum required percentage of Federal Reserve Bank stock to be maintained of total assets	0.20%
Impairment of investments	$ 0	0
Nonmarketable securities	5,700,000	0
Troubled debt restructuring, impaired loans	$ 0	0
Tax benefit realization threshold	50.00%
Unrecognized tax benefits, Income tax penalties and interest accrued	$ 0	$ 0
Number of shares of stock options granted	0	0
Weighted average number of shares outstanding	7,559,310	8,131,334
Options outstanding	0	0
ASU 2019-12 [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2021
Change in accounting principle, accounting standards update, immaterial effect	true
ASU 2020-01 [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2021
Change in accounting principle, accounting standards update, immaterial effect	true
ASU 2020-08 [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2021
Change in accounting principle, accounting standards update, immaterial effect	true
Minimum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Property, plant and equipment, useful life	3 years
Maximum [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Property, plant and equipment, useful life	39 years
Federal Reserve Bank [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Restricted equity securities	$ 4,100,000	$ 3,300,000
Federal Home Loan Bank of Atlanta [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Restricted equity securities	826,000	1,100,000
Community Bankers Bank Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Restricted equity securities	126,800	$ 126,800
Low-Income Housing Tax Credits [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Restricted equity securities	$ 4,900,000
Series A Fixed-Rate Non-Cumulative Perpetual Preferred Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Yield or fixed rate coupon of each preferred share	7.50%