DERIVATIVES - Cash flow hedge accounting (Details) - Derivatives designated as hedging instruments - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Interest rate caps related to customer deposits
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount, derivative asset	$ 300,000	$ 300,000
Fair value	3,385	770
Other assets.
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount, derivative asset	300,000	300,000
Fair value	$ 3,385	$ 770