DERIVATIVES AND HEDGING ACTIVITIES - Non-designated Hedges (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) item	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($) item	Jun. 30, 2021 USD ($)	Feb. 28, 2022 USD ($)	Dec. 31, 2021 USD ($)
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number of participation loans purchased | item	4		4
Participating mortgage loans, mortgage obligations amount	$ 27,000,000.0		$ 27,000,000.0
Gain (Loss) on fair value hedges recognized in earnings	$ 145,000	$ (179,000)	$ 297,000	$ 295,000
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		9			11
Notional amount of derivatives	$ 100,300,000		$ 100,300,000			$ 93,900,000
Valley Bank | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Number Of Loans Acquired | item	7		7
Valley Bank | Interest Rate Swap | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivatives	$ 459,000		$ 459,000			$ 482,000
Number Of Loans Acquired | item	7		7
Number Of Loans Paid Off | item	6		6