Fair Value of Assets and Liabilities - Summary of Carrying Values, Estimated Fair Values and Placement in Fair Value Hierarchy of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financial assets:
Securities available for sale	$ 48,836	$ 51,666
Loans held for sale	22,698	44,766
Loans, net	579,591	544,621
Derivative assets	895	1,414
Financial liabilities:
Deposits	624,679	638,147
FHLBB advances	45,000	50,000
Derivative liabilities	212	84
Level 2 [Member]
Financial assets:
Securities available for sale	48,836	51,666
Loans held for sale	22,698	44,766
Derivative assets	895	1,414
Financial liabilities:
Deposits	624,762	637,538
FHLBB advances	44,378	50,001
Derivative liabilities	212	84
Level 3 [Member]
Financial assets:
Loans, net	569,377	549,674
Fair Value [Member]
Financial assets:
Securities available for sale	48,836	51,666
Loans held for sale	22,698	44,766
Loans, net	569,377	549,674
Derivative assets	895	1,414
Financial liabilities:
Deposits	624,762	637,538
FHLBB advances	44,378	50,001
Derivative liabilities	$ 212	$ 84

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

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Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

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