DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023 USD ($) instrument institution	Sep. 30, 2023 USD ($) instrument institution	Dec. 31, 2022 USD ($) instrument	Dec. 31, 2020 USD ($) instrument
Derivative [Line Items]
Interest rate cash flow hedge expense reclassified to interest income	$ 400	$ 600
Number of variable-rate to fixed-rate swap transactions | instrument	193	193	209
Minimum
Derivative [Line Items]
Remaining maturity period	1 year	1 year
Maximum
Derivative [Line Items]
Remaining maturity period	12 years	12 years
Interest rate swap
Derivative [Line Items]
Notional amount	$ 800,000	$ 800,000	$ 800,000
Number of instruments terminated | instrument				3
Remaining net gain	$ (100)	$ (100)
Number of variable-rate to fixed-rate swap transactions | instrument	0	0	0
Swap Guarantee
Derivative [Line Items]
Number of financial institutions | institution	1	1
Aggregate fair value of swaps to customers	$ 7,700	$ 7,700	$ 10,400
Cash
Derivative [Line Items]
Collateral value against obligations	5,000	5,000
Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	$ 500,000	$ 500,000
Designated as Hedging Instrument | Interest rate products
Derivative [Line Items]
Count | instrument	6	6
Purchase of derivatives		$ 9,700
Notional amount	$ 500,000	$ 500,000
Designated as Hedging Instrument | Interest rate swap
Derivative [Line Items]
Termination value of derivatives				$ 1,300