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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Loans - Summary of Major Classifications of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	$ 331,915		$ 312,370
Net deferred loan costs (fees)	(445)		304
Allowance for loan losses	(2,650)	$ (2,114)	(2,000)	$ (3,018)	$ (3,187)	$ (3,262)
Loans, net	328,820		310,674
Commercial [Member] \| Real Estate [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	183,377		178,882
Commercial [Member] \| Land [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	1,524		1,623
Commercial [Member] \| Other Commercial Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	59,793		34,072
Residential Real Estate [Member] \| First Mortgage [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	59,456		65,450
Residential Real Estate [Member] \| Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	2,965		2,041
Consumer [Member] \| Other Consumer Loan [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	421		611
Consumer [Member] \| Home Equity Lines Of Credit [Member]
Loans and Leases Receivable Disclosure [Line Items]
Loans, gross	$ 24,379		$ 29,691