Borrowings (Narrative - Federal Home Loan Bank Advances) (Details) - USD ($) $ in Thousands		Dec. 31, 2023	Dec. 31, 2022
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank advances		$ 1,190,000	$ 980,000
Interest rate swaps [Member] | Designated as Hedging Instrument [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Notional amount	[1]	120,000	320,000
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank advances		1,190,000	980,000
Unused line of credit with Federal Home Loan Bank		40,000	40,000
Standby letter of credit with FHLB		65,000	215,000
Remaining borrowing capacity with the FHLB		$ 1,100,000	$ 668,300

[1] The fair value of derivative assets includes accrued interest receivable of $239 thousand and $24 thousand, respectively, at December 31, 2023 and 2022. There was no accrued interest payable included in the fair value of derivative liabilities at December 31, 2023, compared to $856 thousand of accrued interest payable at December 31, 2022.