FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS - Valuation technique and additional information (Details) - Nonrecurring - Level 3	Mar. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans	$ 2,553,000	$ 2,394,000
Collateral-dependent loans, valuation allowance	$ 140,000	$ 135,000
Appraisal adjustments | Minimum
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans, measurement input	0.10	0.10
Appraisal adjustments | Maximum
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans, measurement input	0.50	0.55
Appraisal adjustments | Weighted-average
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans, measurement input	(0.26)	(0.26)
Selling costs | Minimum
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans, measurement input	0.07	0.07
Selling costs | Maximum
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans, measurement input	0.15	0.14
Selling costs | Weighted-average
FAIR VALUE MEASUREMENT AND FAIR VALUE OF FINANCIAL INSTRUMENTS
Collateral-dependent loans, measurement input	(0.10)	(0.10)