INVESTMENTS IN LOANS AND SECURITIES - Schedule of Investments in Loans and Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 1,036,164	$ 811,874
Gross Unrealized Gains	15,669	19,313
Gross Unrealized Losses	(31,322)	(13,436)
Allowance for Credit Losses	(126,360)	(100,958)	$ (68,347)	$ 0
Fair Value	894,151	716,793
Accrued interest receivable	$ 14,500	$ 12,500
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Fees and other receivables (including related party receivables of $53,916 and $51,036 as of March 31, 2024 and December 31, 2023, respectively)	Fees and other receivables (including related party receivables of $53,916 and $51,036 as of March 31, 2024 and December 31, 2023, respectively)
Securitization notes
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 174,845	$ 91,654
Gross Unrealized Gains	651	629
Gross Unrealized Losses	(1,684)	(1,858)
Allowance for Credit Losses	0	0	0	0
Fair Value	173,812	90,425
Securitization certificates
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	852,179	715,646
Gross Unrealized Gains	15,018	18,684
Gross Unrealized Losses	(29,638)	(11,578)
Allowance for Credit Losses	(121,349)	(98,679)	(65,572)	0
Fair Value	716,210	624,073
Other loans and receivables
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	9,140	4,574
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Allowance for Credit Losses	(5,011)	(2,279)	$ (2,775)	$ 0
Fair Value	$ 4,129	$ 2,295