Allowance for Loans Losses - Summary of Loan Portfolio Individually and Collectively Evaluated for Impairment (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	$ 671,666	$ 647,572
Less: Unearned income	(731)	(738)
Total	670,935	646,834
Commercial and Industrial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	82,177	77,282
Agricultural [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	309	446
Construction, Commercial [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	42,527	38,039
Construction, Residential [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	27,152	26,778
Mortgage, Commercial [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	256,543	251,824
Mortgage, Residential [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	215,155	208,494
Mortgage, Farmland [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	5,394	5,507
Consumer Installment Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	42,409	39,202
Individually Evaluated for Impairment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	1,077	1,408
Total	1,077	1,408
Individually Evaluated for Impairment [Member] \| Commercial and Industrial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	270	280
Individually Evaluated for Impairment [Member] \| Mortgage, Commercial [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	412	733
Individually Evaluated for Impairment [Member] \| Mortgage, Residential [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	395	395
Collectively Evaluated for Impairment [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	670,589	646,164
Less: Unearned income	(731)	(738)
Total	669,858	645,426
Collectively Evaluated for Impairment [Member] \| Commercial and Industrial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	81,907	77,002
Collectively Evaluated for Impairment [Member] \| Agricultural [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	309	446
Collectively Evaluated for Impairment [Member] \| Construction, Commercial [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	42,527	38,039
Collectively Evaluated for Impairment [Member] \| Construction, Residential [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	27,152	26,778
Collectively Evaluated for Impairment [Member] \| Mortgage, Commercial [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	256,131	251,091
Collectively Evaluated for Impairment [Member] \| Mortgage, Residential [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	214,760	208,099
Collectively Evaluated for Impairment [Member] \| Mortgage, Farmland [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	5,394	5,507
Collectively Evaluated for Impairment [Member] \| Consumer Installment Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Gross loans	$ 42,409	$ 39,202

Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts 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 before allowance and after 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.

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