COMMERCIAL MORTGAGE LOANS HELD-FOR-INVESTMENT - Additional Information (Details) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	Feb. 28, 2023 USD ($)	Sep. 30, 2023 USD ($) loanParticipation	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Sale of loans	$ 6.0
Reserve for impaired loan			$ 4.3
Office Building
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired unpaid principal value	$ 10.3
Reserve for impaired loan		$ 4.3
Multifamily
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired unpaid principal value		$ 68.6
Number of impaired office loans | loanParticipation		3