Loans - Narrative (Details) $ in Thousands	Mar. 31, 2024 USD ($) loan	Dec. 31, 2023 USD ($) loan	Mar. 31, 2023 USD ($) loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net deferred loan costs	$ 11,745	$ 11,479	$ 10,315
Loans used to collateralize borrowings from the Federal Home Loan Bank of Boston	565,047	561,574	527,949
Loans	$ 2,173,746	$ 2,129,454	$ 1,982,847
Number of mortgage loans in the process of foreclosure \| loan	4	5	2
Mortgage loans in the process of foreclosure	$ 510	$ 400	$ 166
Interest rate swap agreements \| Designated as Hedging Instrument
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan adjustments	(618)	1,769	2,774
Interest rate swap agreements \| Fair Value Hedging \| Designated as Hedging Instrument
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan adjustments	313	2,149	3,096
Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 322,124	$ 320,083	$ 373,791

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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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