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DERIVATIVES AND HEDGING ACTIVITIES - Classification on Consolidated Statements of Financial Condition (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) DerivativeInstrument	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) DerivativeInstrument	Jun. 30, 2021 USD ($)	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	$ 1,685,000	$ 559,000	$ 1,691,000	$ 2,351,000
Interest Rate Swaps Related to FHLBNY Advances [Member] \| Designated as Hedging Instrument
Cash Flow Hedges
Count, assets \| DerivativeInstrument	4		4		4
Notional amount, assets	$ 150,000,000		$ 150,000,000		$ 150,000,000
Fair value assets	$ 13,497,000		$ 13,497,000		$ 4,358,000
Loan Level Interest Rate Swaps with Borrower (Assets) \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets	10		10		98
Notional amount, assets	$ 54,115,000		$ 54,115,000		$ 599,003,000
Fair value assets	$ 882,000		$ 882,000		$ 27,440,000
Loan Level Interest Rate Swaps with Borrower (Liabilities) \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, liabilities	175		175		12
Notional amount, liabilities	$ 1,164,869,000		$ 1,164,869,000		$ 100,774,000
Fair value liabilities	(84,162,000)		(84,162,000)		$ (53,000)
Posted collateral	$ 0		$ 0
Loan Level Interest Rate Swaps with Borrower 3 \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, liabilities \| DerivativeInstrument					87
Notional amount, liabilities					$ 612,610,000
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		42		98
Notional amount, liabilities	$ 332,806,000		$ 332,806,000		$ 599,003,000
Fair value liabilities	$ (8,376,000)		$ (8,376,000)		$ (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	10		10
Notional amount, liabilities	$ 54,115,000		$ 54,115,000
Fair value liabilities	(882,000)		(882,000)
Loan Level Interest Rate Swaps with Third-part Counterparties \| Designated as Hedging Instrument
Cash Flow Hedges
Posted collateral	$ 0		$ 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	175		175
Notional amount, assets	$ 1,164,869,000		$ 1,164,869,000		$ 612,610,000
Fair value assets	84,162,000		84,162,000		12,620,000
Posted collateral	0		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 \| DerivativeInstrument					33
Notional amount, liabilities					$ 291,990,000
Fair value liabilities					$ (615,000)
Posted collateral	$ 101,600,000		$ 101,600,000
Loan Level Interest Rate Floors with Third-part Counterparties \| Not Designated as Hedging Instrument [Member]
Cash Flow Hedges
Count, assets	42		42		12
Notional amount, assets	$ 332,806,000		$ 332,806,000		$ 100,774,000
Fair value assets	$ 8,376,000		$ 8,376,000		$ 53,000