LOANS - Geographic Concentrations Based on Unpaid Principal Balances (Details) - Residential mortgage loans - Geographic Concentration Risk	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
All Locations
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Geographic Concentrations of Residential Mortgage Loans	100.00%	100.00%
California
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Geographic Concentrations of Residential Mortgage Loans	39.70%	39.50%
New York
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Geographic Concentrations of Residential Mortgage Loans	11.20%	10.90%
Florida
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Geographic Concentrations of Residential Mortgage Loans	9.10%	10.10%
Texas
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Geographic Concentrations of Residential Mortgage Loans	5.40%	5.40%
All other (none individually greater than 5%)
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Geographic Concentrations of Residential Mortgage Loans	34.60%	34.10%