Loans and Allowance for Loan Losses - Schedule of Categories of Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	$ 441,548	$ 409,683
Less allowance for loan losses	(2,231)	(2,043)	$ (2,122)
Total loans	439,317	407,640
Commercial loans
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	99,995	93,690
Less allowance for loan losses	(568)	(389)	(537)
Commercial real estate
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	254,651	223,461
Less allowance for loan losses	(792)	(672)	(843)
Residential real estate
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	77,205	78,767
Less allowance for loan losses	(572)	(519)	$ (436)
Installment loans
Accounts Notes And Loans Receivable [Line Items]
Total gross loans	$ 9,697	$ 13,765

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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