VARIABLE INTEREST ENTITIES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Variable Interest Entity [Line Items]
Securitized debt of consolidated VIEs	$ 18,709,118		$ 18,709,118		$ 11,600,338	[1]
Costs incurred in connection with securitization	43,921	$ 39,909	127,382	$ 123,652
Securitized debt of consolidated VIE, unrealized gain (loss)	(430,400)	(339,600)	294,900	213,500
Participations issued	467,006		467,006		1,103,835	[1]
Consolidated VIEs
Variable Interest Entity [Line Items]
Exposure to obligations of VIEs	2,100,000		2,100,000
Securitized debt of consolidated VIEs	18,700,000		18,700,000		11,600,000
Costs incurred in connection with securitization	5,000	$ 1,900
Contractual principal amount of debt held by third parties	19,300,000		19,300,000		12,600,000
Consolidated VIEs | OBX Trust
Variable Interest Entity [Line Items]
Costs incurred in connection with securitization			14,000	$ 5,900
Consolidated VIEs | Consolidation, Eliminations
Variable Interest Entity [Line Items]
Mortgage-backed securities	2,100,000		2,100,000		1,400,000
VIE, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Participations issued	$ 500,000		$ 500,000		$ 1,100,000

[1] (1)Derived from the audited consolidated financial statements at December 31, 2023.