FAIR VALUE MEASUREMENTS - Schedule of Estimated Change in Fair Value of Interests in the Agency MSRs, Non-Agency MSRs and Ginnie Mae MSRs (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ 9,693,331	$ 8,405,938
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	6,079,335
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Twenty Percent Decrease In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	6,601,506
Amount	$ 522,171
Percentage	8.60%
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Twenty Percent Decrease In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,363,422
Amount	$ 284,087
Percentage	4.70%
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Twenty Percent Decrease In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,096,639
Amount	$ 17,304
Percentage	0.30%
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Ten Percent Decrease In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,344,320
Amount	$ 264,985
Percentage	4.40%
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Ten Percent Decrease In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,216,274
Amount	$ 136,939
Percentage	2.30%
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Ten Percent Decrease In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,088,185
Amount	$ 8,850
Percentage	0.10%
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Ten Percent Increase In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 5,835,324
Amount	$ (244,011)
Percentage	(4.00%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Ten Percent Increase In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 5,951,290
Amount	$ (128,045)
Percentage	(2.10%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Ten Percent Increase In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,070,197
Amount	$ (9,138)
Percentage	(0.20%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Twenty Percent Increase In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 5,609,934
Amount	$ (469,401)
Percentage	(7.70%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Twenty Percent Increase In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 5,831,466
Amount	$ (247,869)
Percentage	(4.10%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Agency | Twenty Percent Increase In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 6,060,853
Amount	$ (18,482)
Percentage	(0.30%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ 885,053
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Twenty Percent Decrease In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	978,489
Amount	$ 93,436
Percentage	10.60%
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Twenty Percent Decrease In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 939,289
Amount	$ 54,236
Percentage	6.10%
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Twenty Percent Decrease In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 900,052
Amount	$ 14,999
Percentage	1.70%
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Ten Percent Decrease In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 929,530
Amount	$ 44,477
Percentage	5.00%
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Ten Percent Decrease In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 911,268
Amount	$ 26,215
Percentage	3.00%
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Ten Percent Decrease In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 892,478
Amount	$ 7,425
Percentage	0.80%
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Ten Percent Increase In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 844,090
Amount	$ (40,963)
Percentage	(4.60%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Ten Percent Increase In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 860,064
Amount	$ (24,989)
Percentage	(2.80%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Ten Percent Increase In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 877,898
Amount	$ (7,155)
Percentage	(0.80%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Twenty Percent Increase In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 806,673
Amount	$ (78,380)
Percentage	(8.90%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Twenty Percent Increase In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 836,525
Amount	$ (48,528)
Percentage	(5.50%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Non-Agency | Twenty Percent Increase In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 870,916
Amount	$ (14,137)
Percentage	(1.60%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value	$ 2,728,943
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Twenty Percent Decrease In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	2,966,767
Amount	$ 237,824
Percentage	8.70%
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Twenty Percent Decrease In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,888,042
Amount	$ 159,099
Percentage	5.80%
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Twenty Percent Decrease In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,774,102
Amount	$ 45,159
Percentage	1.70%
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Ten Percent Decrease In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,842,986
Amount	$ 114,043
Percentage	4.20%
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Ten Percent Decrease In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,804,727
Amount	$ 75,784
Percentage	2.80%
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Ten Percent Decrease In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,751,475
Amount	$ 22,532
Percentage	0.80%
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Ten Percent Increase In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,623,622
Amount	$ (105,321)
Percentage	(3.90%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Ten Percent Increase In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,659,509
Amount	$ (69,434)
Percentage	(2.50%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Ten Percent Increase In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,706,569
Amount	$ (22,374)
Percentage	(0.80%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Twenty Percent Increase In Measurement Input | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,526,134
Amount	$ (202,809)
Percentage	(7.40%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Twenty Percent Increase In Measurement Input | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,595,473
Amount	$ (133,470)
Percentage	(4.90%)
MSRs, MSR Financing Receivables, Excess Spread Financing | Ginnie Mae | Twenty Percent Increase In Measurement Input | Delinquency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value	$ 2,684,392
Amount	$ (44,551)
Percentage	(1.60%)