Financial Transactions with Off-Balance-Sheet Risk and Concentrations of Credit Risk - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Derivative liabilities, at fair value, net	$ (6,100,000)	$ (684,000)
Off-balance sheet, credit loss, liability	5,484,000	6,970,000	$ 524,000
(Reversal of) provision for credit losses	(1,486,000)	(1,228,000)
Disposal Group, Held-for-sale, Not Discontinued Operations
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	0
Unused lines of Credit
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	1,300,000,000	1,200,000,000
Mortgages
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	0
Letter of Credit
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	33,100,000	20,400,000
Letter of Credit | Columbia Bank's New Jersey Public Fund
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	575,000,000
Letter of Credit | New Jersey Governmental Unit Deposit Protection Act
Loss Contingencies [Line Items]
Fair value disclosure, off-balance sheet risk, amount, liability	$ 600,000	$ 600,000