DERIVATIVE INSTRUMENTS - Effect of Other Derivative Contracts on the Consolidated Statements of Operations and Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Unrealized Gain (Loss)	$ 1,001,988	$ (815,630)	$ 3,480,708
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Other Derivatives	$ 124,895	(294,574)
Derivative, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net gains (losses) on derivatives
Futures
Derivative [Line Items]
Realized Gain (Loss)	$ (96,667)	194,316
Unrealized Gain (Loss)	354,164	(201,095)
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Other Derivatives	257,497	(6,779)
Futures | Secured Overnight Financing Rate (SOFR)
Derivative [Line Items]
Realized Gain (Loss)	(6,800)
Purchase commitments
Derivative [Line Items]
Realized Gain (Loss)	0	0
Unrealized Gain (Loss)	(9,975)	7,932
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Other Derivatives	(9,975)	7,932
TBA derivatives
Derivative [Line Items]
Realized Gain (Loss)	(13,220)	(174,666)
Unrealized Gain (Loss)	(3,524)	33,833
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Other Derivatives	(16,744)	(140,833)
Interest rate swaptions
Derivative [Line Items]
Realized Gain (Loss)	(37,401)	(29,438)
Unrealized Gain (Loss)	(68,482)	(119,348)
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Other Derivatives	$ (105,883)	(148,786)
Credit derivatives
Derivative [Line Items]
Realized Gain (Loss)		(19,368)
Unrealized Gain (Loss)		13,260
Amount of Gain/(Loss) Recognized in Net Gains (Losses) on Other Derivatives		$ (6,108)