Borrowings (Narrative) (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	$ 1,550,000	$ 1,190,000
Interest rate swaps \| Designated as Cash Flow Hedging Instruments
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Notional amount	120,000	120,000
Interest rate collar \| Designated as Cash Flow Hedging Instruments
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Notional amount	50,000	0
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Branch of FHLBB Bank [Line Items]
Federal Home Loan Bank advances	1,550,000	1,200,000
Unused line of credit with FHLB	40,000	40,000
Standby letter of credit with FHLB	66,000	65,000
Unused remaining available borrowing capacity with FHLB	$ 801,500	$ 1,100,000

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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Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
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Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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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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