DERIVATIVE INSTRUMENTS - Effect of Other Derivative Contracts on the Consolidated Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Derivative [Line Items]
Unrealized Gain (Loss)	$ 97,484	$ 841,702	$ 998,386	$ (114,570)
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Derivatives	15,910	160,182	183,240	(24,185)
Futures
Derivative [Line Items]
Realized Gain (Loss)	48,227	(242,013)	39,547	(123,681)
Unrealized Gain (Loss)	(45,882)	413,240	99,827	98,362
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Derivatives	2,345	171,227	139,374	(25,319)
Futures | Secured Overnight Financing Rate (SOFR)
Derivative [Line Items]
Realized Gain (Loss)	(6,800)		(6,800)
Unrealized Gain (Loss)	(1,200)		(18,800)	(18,800)
Purchase commitments
Derivative [Line Items]
Realized Gain (Loss)	0	0	0	0
Unrealized Gain (Loss)	2,360	(3,444)	(4,252)	(2,581)
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Derivatives	2,360	(3,444)	(4,252)	(2,581)
Net TBA derivatives
Derivative [Line Items]
Realized Gain (Loss)	(16,252)	99,361	(24,868)	(54,488)
Unrealized Gain (Loss)	15,931	(160,873)	30,829	54,487
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Derivatives	(321)	(61,512)	5,961	(1)
Net interest rate swaptions
Derivative [Line Items]
Realized Gain (Loss)	(12,331)	0	(12,331)	2,323
Unrealized Gain (Loss)	23,857	53,413	54,488	7,415
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Derivatives	$ 11,526	53,413	$ 42,157	9,738
Credit derivatives
Derivative [Line Items]
Realized Gain (Loss)		(17,970)		(19,282)
Unrealized Gain (Loss)		18,468		13,260
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Derivatives		$ 498		$ (6,022)