FAIR VALUE MEASUREMENTS - Real Estate And Other Securities Valuation Methodology and Results (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2025 USD ($) source	Dec. 31, 2024 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Outstanding Face Amount	$ 16,909,542	$ 15,878,274
Amortized Cost Basis	8,551,600	7,259,894
Government and government-backed securities	$ 8,663,224	7,245,667
Number of broker quotation sources | source	2
Multiple Quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	$ 8,549,074	7,196,838
Single Quote
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	114,150	48,829
Agency
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Outstanding Face Amount	7,717,430	6,672,189
Amortized Cost Basis	7,533,795	6,510,235
Agency | Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	7,586,689	6,450,643
Agency | Level 2 | Multiple Quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	7,586,689	6,450,643
Agency | Level 2 | Single Quote
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	0	0
Collateral
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Outstanding Face Amount	339,429	243,355
Amortized Cost Basis	328,123	234,397
Collateral | Fair Value, Inputs, Level 2 and 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	337,392	242,227
Collateral | Fair Value, Inputs, Level 2 and 3 | Multiple Quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	249,627	217,049
Collateral | Fair Value, Inputs, Level 2 and 3 | Single Quote
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	87,765	25,178
Non-Agency Securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Outstanding Face Amount	8,852,683	8,962,730
Amortized Cost Basis	$ 689,682	$ 515,262
Percent of securities	81.90%	82.10%
Fair Value	$ 605,081	$ 453,978
Non-Agency Securities | Minimum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.047	0.047
Non-Agency Securities | Minimum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.000	0.000
Non-Agency Securities | Minimum | CDR
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.000	0.000
Non-Agency Securities | Minimum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.000	0.000
Non-Agency Securities | Maximum | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.209	0.200
Non-Agency Securities | Maximum | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.250	0.200
Non-Agency Securities | Maximum | CDR
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.019	0.019
Non-Agency Securities | Maximum | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.500	0.500
Non-Agency Securities | Weighted Average | Discount Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.067	0.069
Non-Agency Securities | Weighted Average | Prepayment Rate
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.066	0.063
Non-Agency Securities | Weighted Average | CDR
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.003	0.005
Non-Agency Securities | Weighted Average | Loss Severity
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount Rate	0.112	0.170
Non-Agency Securities | Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	$ 739,143	$ 552,797
Non-Agency Securities | Level 3 | Multiple Quotes
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	712,758	529,146
Non-Agency Securities | Level 3 | Single Quote
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Government and government-backed securities	$ 26,385	$ 23,651
Residential Mortgage Loans HFS, at Fair Value | Minimum | Discount Rate | Non-performing loans | Acquired loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.092	0.085
Residential Mortgage Loans HFS, at Fair Value | Minimum | CDR | Non-performing loans | Acquired loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.031	0.013
Residential Mortgage Loans HFS, at Fair Value | Maximum | Discount Rate | Non-performing loans | Acquired loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.120	0.093
Residential Mortgage Loans HFS, at Fair Value | Maximum | CDR | Non-performing loans | Acquired loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.059	0.051
Residential Mortgage Loans HFS, at Fair Value | Weighted Average | Discount Rate | Non-performing loans | Acquired loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.111	0.088
Residential Mortgage Loans HFS, at Fair Value | Weighted Average | CDR | Non-performing loans | Acquired loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Loans held-for-sale, measurement input	0.049	0.038