FAIR VALUE - Summary of assets measured at level 3 fair value on recurring basis (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Summary of assets measured on a recurring and nonrecurring basis
Other real estate owned, gross	$ 0		$ 0
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net income available for common shareholders	Net income available for common shareholders
Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	$ 33,569,000		39,656,000
Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	33,569,000		39,656,000
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Loans Held at Fair Value
Summary of assets measured on a recurring and nonrecurring basis
Settlements	352,000	$ 392,000
Settlements	(1,502,000)	(3,134,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	11,922,000	20,807,000	13,726,000	$ 23,321,000
Loans acquired	0	1,162,000
Gains/(losses) in net income, net	50,000	(150,000)
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Guarantee Asset
Summary of assets measured on a recurring and nonrecurring basis
Settlements	(8,000)	(5,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	199,000	235,000	189,000	143,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	(13,000)	(5,000)
Gains/(losses) in net income, net	5,000	92,000
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | IRLC, net
Summary of assets measured on a recurring and nonrecurring basis
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	813,000	723,000	345,000	229,000
Loans acquired	813,000	886,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances	(819,000)	(1,486,000)
Gains/(losses) in net income, net	474,000	1,094,000
Significant Unobservable Inputs (Level 3) | Fair Value, Recurring | Equity Warrants
Summary of assets measured on a recurring and nonrecurring basis
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	795,000	$ 825,000	795,000	$ 825,000
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	0		0
Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	0		0
Commercial | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	23,353,000		25,738,000
Commercial | Significant Unobservable Inputs (Level 3) | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	23,353,000		25,738,000
Commercial | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	0		0
Commercial | Significant Other Observable Inputs (Level 2) | Fair Value, Nonrecurring
Summary of assets measured on a recurring and nonrecurring basis
Net recorded investment	$ 0		$ 0