COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Concentration of Credit Risk (Details) - Commercial Loans Held-For-Investment - Commercial Real Estate Portfolio Segment	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	100.00%	100.00%
Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	100.00%	100.00%
Multifamily | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	91.70%	92.30%
Seniors Housing and Healthcare | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	7.70%	7.10%
Self-Storage | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	0.60%	0.60%
South | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	35.70%	36.60%
Southwest | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	32.30%	32.90%
Mid-Atlantic | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	17.10%	16.10%
Midwest | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	7.90%	7.70%
West | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	7.00%	6.70%