Loans - Summary of Allowance for Loan and Lease Losses for Loans Evaluated Individually and Collectively for Impairment (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Loans and Leases Receivable Disclosure [Line Items]
Individually evaluated for impairment	$ 7,386	$ 8,041
Collectively evaluated for impairment	297,283	304,329
Total loans	304,669	312,370
Individually evaluated for impairment	67	67
Collectively evaluated for impairment	1,941	1,933
Total allowance for loan losses	2,008	2,000	$ 3,426	$ 3,262
Commercial [Member]
Loans and Leases Receivable Disclosure [Line Items]
Individually evaluated for impairment	6,693	6,931
Collectively evaluated for impairment	208,153	207,646
Total loans	214,846	214,577
Collectively evaluated for impairment	1,241	1,235
Total allowance for loan losses	1,241	1,235	1,644	1,448
Residential [Member]
Loans and Leases Receivable Disclosure [Line Items]
Individually evaluated for impairment	661	1,078
Collectively evaluated for impairment	59,625	66,413
Total loans	60,286	67,491
Individually evaluated for impairment	62	62
Collectively evaluated for impairment	511	511
Total allowance for loan losses	573	573	1,213	1,250
Consumer [Member]
Loans and Leases Receivable Disclosure [Line Items]
Individually evaluated for impairment	32	32
Collectively evaluated for impairment	29,505	30,270
Total loans	29,537	30,302
Individually evaluated for impairment	5	5
Collectively evaluated for impairment	189	187
Total allowance for loan losses	$ 194	$ 192	$ 569	$ 564

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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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, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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