COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Summary of Concentration of Credit Risk (Details) - Commercial Loans Held-For-Investment - Commercial Real Estate Portfolio Segment	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
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	93.20%	94.00%
Seniors Housing and Healthcare | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	6.30%	5.50%
Self-Storage | Collateral Property Type
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	0.50%	0.50%
South | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	38.70%	43.50%
Southwest | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	34.20%	29.40%
Mid-Atlantic | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	14.20%	15.00%
Midwest | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	8.00%	7.90%
West | Geography
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration risk, percent	4.90%	4.20%