Borrowings (Narrative) (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	$ 576,000	$ 626,000
Federal Home Loan Bank of Boston
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	576,000	626,000
Unused remaining available borrowing capacity with FHLB	1,400,000	1,400,000
Unused line of credit with FHLB	40,000	40,000
Standby letter of credit with FHLB	$ 65,100	$ 66,000

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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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.

+ References

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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 10
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The amount remaining to be drawn on at the balance sheet date associated with a standby letter of credit with the FHLB.

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