Loans and Allowance for Loan Losses - Schedule of Categories of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	$ 462,119		$ 443,491
Less allowance for loan losses	(4,123)	$ (4,542)	(5,113)	$ (5,228)	$ (4,015)	$ (2,231)
Total loans	457,996		438,378
Commercial
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	99,880		103,277
Less allowance for loan losses	(894)	(1,140)	(1,397)	(1,321)	(2,344)	(568)
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	266,023		246,167
Less allowance for loan losses	(1,555)	(1,710)	(1,821)	(1,890)	(751)	(792)
Residential
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	89,280		85,789
Less allowance for loan losses	(1,319)	$ (1,353)	(1,471)	$ (1,568)	$ (600)	$ (572)
Installment loans
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	$ 6,936		$ 8,258