Loans - Narrative (Details) $ in Thousands	Sep. 30, 2024 USD ($) loan	Dec. 31, 2023 USD ($) loan	Sep. 30, 2023 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net deferred loan costs	$ 12,266	$ 11,479	$ 11,213
Loans used to collateralize borrowings from the Federal Home Loan Bank of Boston	622,370	561,574	525,904
Loans	$ 2,307,253	$ 2,129,454	$ 2,079,860
Number of mortgage loans in the process of foreclosure \| loan	2	5	4
Mortgage loans in the process of foreclosure	$ 127	$ 400	$ 459
Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	364,068	320,083	332,657
Interest rate swap agreements \| Designated as Hedging Instrument
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value	(2,634)	(1,769)	2,489
Interest rate swap agreements \| Fair Value Hedging \| Designated as Hedging Instrument
Accounts, Notes, Loans and Financing Receivable [Line Items]
Fair Value	$ (2,462)	$ (2,149)	$ 705

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of the assets less the liabilities of a derivative or group of derivatives.

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Amount of fee received for commitment to originate or purchase financing receivable where likelihood of commitment being exercised is remote, to be recognized as service income.

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Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

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