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Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest-bearing deposits maturing date	90 days
Transfer of assets into or out of level 3	$ 0	$ 0
Transfer of liabilities into or out of level 3	0	0
Collateral dependent impaired loans categorized as Level 3	3,061,000	2,054,000
Specific allocation for collateral dependent impaired loans	197,000	31,000
Asset impairment charges	0
Collateral Dependent [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Specific allocation for collateral dependent impaired loans	197,000	31,000
Level 3 [Member] | Collateral Dependent [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent impaired loans categorized as Level 3	$ 444,000	$ 215,000

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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-Topic 230
-SubTopic 10
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Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

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