DERIVATIVES AND HEDGING ACTIVITIES - Non-designated Hedges (Details)	3 Months Ended
	Mar. 31, 2022 USD ($) item	Mar. 31, 2021 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2021 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number Of Participation Loans Purchased | item	4
Participating mortgage loans, mortgage obligations amount	$ 27,100,000
Gain (Loss) on fair value hedges recognized in earnings	$ 152,000	$ 474,000
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivatives			$ 300,000,000
Interest Rate Swap | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of interest rate derivatives held	9			11
Notional amount of derivatives	$ 94,200,000			$ 93,900,000
Valley Bank | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number Of Loans Acquired | item	7
Valley Bank | Interest Rate Swap | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivatives	$ 468,000			$ 482,000
Number Of Loans Acquired | item	7
Number Of Loans Paid Off | item	6