Fair Value - Significant Unobservable Inputs (Details) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2026 USD ($)	Dec. 31, 2025 USD ($)
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities	$ 86,717	$ 88,283
Woodstar Fund investments	1,729,433	1,727,499
Domestic servicing rights	27,743	28,280
VIE assets	32,399,812	34,493,164
VIE liabilities	30,768,059	32,803,806
RMBS
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities	86,717	88,283
CMBS
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities	38,764	32,522
Domestic servicing rights
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Domestic servicing rights	27,743	28,280
Level III
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	2,311,351
Woodstar Fund investments	1,729,433	1,727,499
VIE assets	32,399,812	34,493,164
VIE liabilities	$ 3,759,883	$ 3,831,053
Level III \| Direct capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.0499
Level III \| Implied capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.0499
Level III \| Minimum
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option, duration	2 years	2 years 3 months 18 days
VIE assets duration	0 years	0 years
VIE liabilities duration	0 years	0 years
Level III \| Minimum \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	0.028	0.028
VIE assets	0	0
VIE liabilities	0	0
Level III \| Minimum \| FICO score
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	585	585
Level III \| Minimum \| LTV
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	0.02	0.01
Level III \| Minimum \| Purchase price
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	0.800	0.800
Level III \| Minimum \| Discount rate - properties
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.070
Level III \| Minimum \| Discount rate - debt
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.032	0.032
Level III \| Minimum \| Terminal capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.050
Level III \| Maximum
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option, duration	36 years 3 months 18 days	36 years 6 months
VIE assets duration	9 years 8 months 12 days	8 years
VIE liabilities duration	9 years 8 months 12 days	8 years
Level III \| Maximum \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	0.108	0.108
VIE assets	6.494	4.201
VIE liabilities	6.494	4.201
Level III \| Maximum \| FICO score
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	829	829
Level III \| Maximum \| LTV
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	1	1
Level III \| Maximum \| Purchase price
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	1.068	1.068
Level III \| Maximum \| Discount rate - properties
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.078
Level III \| Maximum \| Discount rate - debt
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.059	0.056
Level III \| Maximum \| Terminal capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.058
Level III \| Weighted-average
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option, duration	24 years 9 months 18 days	25 years 6 months
VIE assets duration	3 years 4 months 24 days	3 years 3 months 18 days
VIE liabilities duration	3 years	2 years 10 months 24 days
Level III \| Weighted-average \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	0.045	0.045
VIE assets	0.176	0.221
VIE liabilities	0.106	0.121
Level III \| Weighted-average \| FICO score
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	750	750
Level III \| Weighted-average \| LTV
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	0.63	0.63
Level III \| Weighted-average \| Purchase price
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Loans under fair value option	1.013	1.013
Level III \| Weighted-average \| Discount rate - properties
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.075
Level III \| Weighted-average \| Discount rate - debt
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.051	0.049
Level III \| Weighted-average \| Terminal capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.055
Level III \| Weighted-average \| Direct capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.0499
Level III \| Weighted-average \| Implied capitalization rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input		0.0499
Level III \| RMBS
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities	$ 86,717	$ 88,283
Level III \| RMBS \| Minimum \| Constant prepayment rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.022	0.022
Level III \| RMBS \| Minimum \| Constant default rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.008	0.007
Level III \| RMBS \| Minimum \| Loss severity
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0	0
Level III \| RMBS \| Minimum \| Delinquency rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.07	0.07
Level III \| RMBS \| Minimum \| Servicer advances
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.27	0.31
Level III \| RMBS \| Maximum \| Constant prepayment rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.107	0.110
Level III \| RMBS \| Maximum \| Constant default rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.124	0.075
Level III \| RMBS \| Maximum \| Loss severity
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	1.34	0.81
Level III \| RMBS \| Maximum \| Delinquency rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.24	0.24
Level III \| RMBS \| Maximum \| Servicer advances
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.71	0.70
Level III \| RMBS \| Weighted-average \| Constant prepayment rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.046	0.046
Level III \| RMBS \| Weighted-average \| Constant default rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.015	0.015
Level III \| RMBS \| Weighted-average \| Loss severity
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.11	0.10
Level III \| RMBS \| Weighted-average \| Delinquency rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.13	0.13
Level III \| RMBS \| Weighted-average \| Servicer advances
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.49	0.49
Level III \| CMBS
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities	$ 32,237	$ 28,197
Level III \| CMBS \| Minimum
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
CMBS, term	0 years	0 years
Level III \| CMBS \| Minimum \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0	0
Level III \| CMBS \| Maximum
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
CMBS, term	6 years 2 months 12 days	6 years 8 months 12 days
Level III \| CMBS \| Maximum \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.899	0.639
Level III \| CMBS \| Weighted-average
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
CMBS, term	1 year 3 months 18 days	1 year 3 months 18 days
Level III \| CMBS \| Weighted-average \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Available-for-sale securities, measurement input	0.250	0.107
Level III \| Domestic servicing rights
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Domestic servicing rights	$ 27,743	$ 28,280
Level III \| Domestic servicing rights \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Domestic servicing rights	0.0900	0.0900
Level III \| Domestic servicing rights \| Discount rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Domestic servicing rights	0.15	0.15
Level III \| Domestic servicing rights \| Weighted-average \| Debt yield
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Domestic servicing rights	0.0900	0.0900
Level III \| Domestic servicing rights \| Weighted-average \| Discount rate
Quantitative information for Level 3 Fair Value Measurements for assets and liabilities measured at fair value on recurring basis
Domestic servicing rights	0.15	0.15

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