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DERIVATIVES AND HEDGING ACTIVITIES - Classification on Consolidated Statements of Financial Condition (Details)	3 Months Ended
	Mar. 31, 2022 USD ($) DerivativeInstrument	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) DerivativeInstrument
Cash Flow Hedges
Collateral received against obligations in net asset position			$ 4,600,000
Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Loan level derivative income	$ 6,000	$ 1,792,000
Interest Rate Swaps Related to FHLBNY Advances [Member] \| Designated as Hedging Instrument
Cash Flow Hedges
Count, assets \| DerivativeInstrument	4		4
Notional amount, assets	$ 150,000,000		$ 150,000,000
Fair value assets	$ 11,240,000		$ 4,358,000
Loan Level Interest Rate Swaps with Borrower (Assets) \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets	20		98
Notional amount, assets	$ 115,621,000		$ 599,003,000
Fair value assets	$ 4,258,000		$ 27,440,000
Loan Level Interest Rate Swaps with Borrower (Liabilities) \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, liabilities	162		12
Notional amount, liabilities	$ 1,051,421,000		$ 100,774,000
Fair value liabilities	(50,760,000)		$ (53,000)
Posted collateral	$ 0
Loan Level Interest Rate Swaps with Borrower 3 \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets	1
Count, liabilities \| DerivativeInstrument			87
Notional amount, assets	$ 23,769,000
Notional amount, liabilities			$ 612,610,000
Fair value assets	$ 9,000
Fair value liabilities			$ (12,620,000)
Loan Level Interest Rate Floors with Borrower \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, liabilities	42		98
Notional amount, liabilities	$ 334,329,000		$ 599,003,000
Fair value liabilities	$ (5,559,000)		$ (27,440,000)
Loan Level Interest Rate Floors with Borrower 2 \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets \| DerivativeInstrument			33
Notional amount, assets			$ 291,990,000
Fair value assets			$ 615,000
Loan Level Interest Rate Swaps with Third-part Counterparties 2 \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, liabilities	20
Notional amount, liabilities	$ 115,621,000
Fair value liabilities	(4,258,000)
Loan Level Interest Rate Swaps with Third-part Counterparties \| Designated as Hedging Instrument
Cash Flow Hedges
Posted collateral	$ 0	$ 0
Loan Level Interest Rate Swaps with Third-part Counterparties \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets \| DerivativeInstrument			87
Count, liabilities	162
Notional amount, assets	$ 1,051,421,000		$ 612,610,000
Fair value assets	50,760,000		12,620,000
Posted collateral	$ 0		$ 14,000,000.0
Loan level interest rate swaps with third party counterparties (Assets) \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets	1		33
Notional amount, liabilities	$ 23,769,000		$ 291,990,000
Fair value liabilities	(9,000)		$ (615,000)
Posted collateral	$ 53,200,000
Loan Level Interest Rate Floors with Third-part Counterparties \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets	42		12
Notional amount, assets	$ 334,329,000		$ 100,774,000
Fair value assets	$ 5,559,000		$ 53,000