v3.26.1
Valuation (Schedule of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3
6 Months Ended
Jun. 30, 2026
USD ($)
$ / shares
Non-Agency RMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 396,915,000
CMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value 10,345,000
CLOs  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value 44,632,000
Asset-backed securities, backed by consumer loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value 170,075,000
Corporate debt and equity  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 40,302,000
Corporate debt and equity | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.025
Corporate debt and equity | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.749
Corporate debt and equity | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.186
Investment in unconsolidated entities  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 402,259,000
Other secured borrowings, at fair value  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ (3,451,333,000)
Other secured borrowings, at fair value | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.049
Other secured borrowings, at fair value | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.547
Other secured borrowings, at fair value | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.056
Other secured borrowings, at fair value | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.152
Other secured borrowings, at fair value | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.755
Other secured borrowings, at fair value | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.554
Agency Interest Only RMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 12,760,000
Valuation, Market Approach | Non-Agency RMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 160,060,000
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 0.46
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 191.00
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 37.23
Valuation, Market Approach | CMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 9,992,000
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 3.05
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 83.90
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 38.32
Valuation, Market Approach | CLOs  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 37,342,000
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 0.01
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 121.16
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 69.45
Valuation, Market Approach | Asset-backed securities, backed by consumer loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 92,067,000
Valuation, Market Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 2.14
Valuation, Market Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 100.10
Valuation, Market Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 71.30
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.50
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 100.07
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 92.64
Valuation, Market Approach | Other secured borrowings, at fair value | Recent transactions  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ (171,989,000)
Valuation, Market Approach | Other secured borrowings, at fair value | Market quotes  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value (3,279,344,000)
Valuation, Market Approach | Unsecured Borrowings  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ (654,962,000)
Valuation, Market Approach | Unsecured Borrowings | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 84.52
Valuation, Market Approach | Unsecured Borrowings | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 99.63
Valuation, Market Approach | Unsecured Borrowings | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 98.86
Valuation, Market Approach | Agency Interest Only RMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 7,088,000
Valuation, Market Approach | Agency Interest Only RMBS | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 1.72
Valuation, Market Approach | Agency Interest Only RMBS | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 21.32
Valuation, Market Approach | Agency Interest Only RMBS | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input | $ / shares 12.40
Valuation, Income Approach | Non-Agency RMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 236,855,000
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.001
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.871
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.162
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.900
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.827
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Default Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Default Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.574
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Default Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.041
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.496
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.031
Valuation, Income Approach | CMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 353,000
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.068
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.238
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.161
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.930
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.114
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.070
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 1.000
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.878
Valuation, Income Approach | CLOs  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 7,290,000
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.116
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.791
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.163
Valuation, Income Approach | Agency RMBS | Measurement Input, LIBOR OAS | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.0109
Valuation, Income Approach | Agency RMBS | Measurement Input, LIBOR OAS | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.3258
Valuation, Income Approach | Agency RMBS | Measurement Input, LIBOR OAS | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.0513
Valuation, Income Approach | Asset-backed securities, backed by consumer loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 78,008,000
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.512
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.105
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.598
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.168
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.000
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.442
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.190
Valuation, Income Approach | Corporate debt and equity  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 37,851,000
Valuation, Income Approach | Consumer loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 108,000
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.118
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.120
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.120
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.268
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.098
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.008
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.642
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.221
Valuation, Income Approach | Corporate loan [Member]  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 52,575,000
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.276
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.111
Valuation, Income Approach | Credit default swaps on asset-backed securities  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ (2,000)
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.229
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.229
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.229
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Default Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.086
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Default Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.086
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Default Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.086
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Projected Collateral Recoveries | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.123
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Projected Collateral Recoveries | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.123
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Projected Collateral Recoveries | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Derivative Liability, Measurement Input 0.123
Valuation, Income Approach | Total return swaps  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ 63,000
Valuation, Income Approach | Total return swaps | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.301
Valuation, Income Approach | Total return swaps | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.301
Valuation, Income Approach | Total return swaps | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.301
Valuation, Income Approach | HECM loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 11,301,352,000
Valuation, Income Approach | HECM loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.028
Valuation, Income Approach | HECM loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.065
Valuation, Income Approach | HECM loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.043
Valuation, Income Approach | HECM loans | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.018
Valuation, Income Approach | HECM loans | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.394
Valuation, Income Approach | HECM loans | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.077
Valuation, Income Approach | Mortgage servicing rights  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 30,040,000
Valuation, Income Approach | Mortgage servicing rights | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.174
Valuation, Income Approach | Mortgage servicing rights | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.174
Valuation, Income Approach | Mortgage servicing rights | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.174
Valuation, Income Approach | Mortgage servicing rights | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.104
Valuation, Income Approach | Mortgage servicing rights | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.423
Valuation, Income Approach | Mortgage servicing rights | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Servicing Asset, Measurement Input 0.146
Valuation, Income Approach | Loan commitments  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 10,191,000
Valuation, Income Approach | Loan commitments | Measurement Input pullthrough rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Commitments, Measurement Input 0.660
Valuation, Income Approach | Loan commitments | Measurement Input pullthrough rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Commitments, Measurement Input 0.944
Valuation, Income Approach | Loan commitments | Measurement Input pullthrough rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Commitments, Measurement Input 0.690
Valuation, Income Approach | Loan commitments | measurement input cost to originate loan | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Commitments, Measurement Input 0.043
Valuation, Income Approach | Loan commitments | measurement input cost to originate loan | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Commitments, Measurement Input 0.105
Valuation, Income Approach | Loan commitments | measurement input cost to originate loan | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Commitments, Measurement Input 0.059
Valuation, Income Approach | HMBS-related obligations  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ (11,057,752,000)
Valuation, Income Approach | HMBS-related obligations | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.026
Valuation, Income Approach | HMBS-related obligations | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.065
Valuation, Income Approach | HMBS-related obligations | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.042
Valuation, Income Approach | HMBS-related obligations | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.069
Valuation, Income Approach | HMBS-related obligations | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.394
Valuation, Income Approach | HMBS-related obligations | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Debt instrument, measurement input 0.077
Valuation, Income Approach | HECM buyout loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 48,178,000
Valuation, Income Approach | HECM buyout loans | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 1 month 18 days
Valuation, Income Approach | HECM buyout loans | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 370 months 6 days
Valuation, Income Approach | HECM buyout loans | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 24 months 6 days
Valuation, Income Approach | HECM buyout loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.062
Valuation, Income Approach | HECM buyout loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.114
Valuation, Income Approach | HECM buyout loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.082
Valuation, Income Approach | Forward MSR-related Investments  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 75,901,000
Valuation, Income Approach | Forward MSR-related Investments | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Forward MSR-related Investments, Value Input 0.090
Valuation, Income Approach | Forward MSR-related Investments | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Forward MSR-related Investments, Value Input 0.090
Valuation, Income Approach | Forward MSR-related Investments | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Forward MSR-related Investments, Value Input 0.090
Valuation, Income Approach | Forward MSR-related Investments | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Forward MSR-related Investments, Value Input 0.050
Valuation, Income Approach | Forward MSR-related Investments | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Forward MSR-related Investments, Value Input 0.050
Valuation, Income Approach | Forward MSR-related Investments | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Forward MSR-related Investments, Value Input 0.050
Valuation, Income Approach | Loan Purchase Commitments  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Financial and Nonfinancial Liabilities, Fair Value Disclosure $ 472,000
Valuation, Income Approach | Agency Interest Only RMBS  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 5,672,000
Valuation, Income Approach | Agency Interest Only RMBS | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.100
Valuation, Income Approach | Agency Interest Only RMBS | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.966
Valuation, Income Approach | Agency Interest Only RMBS | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Securities, measurement input 0.578
Enterprise Value | Corporate debt and equity | Measurement Input, Equity Price-to-Book  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 2,451,000
Enterprise Value | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value 81,205,000
Value of investments excluded from range calculation 400,000
Enterprise Value | Investment in unconsolidated entities | Measurement Input, Net Asset Value  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 321,054,000
measurement input equity multiple | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Equity method investment, measurement input 0.5
measurement input equity multiple | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Equity method investment, measurement input 2.3
measurement input equity multiple | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Equity method investment, measurement input 2.1
Valuation, Cost Approach | Loan Purchase Commitments | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Purchase Commitments, Measurement Input 0.064
Valuation, Cost Approach | Loan Purchase Commitments | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Purchase Commitments, Measurement Input 0.070
Valuation, Cost Approach | Loan Purchase Commitments | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loan Purchase Commitments, Measurement Input 0.067
Including amounts excluded from range calculation | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Equity method investment, measurement input 2.0
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 621,727,000
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.072
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.108
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.087
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 1,841,908,000
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.015
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.650
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.068
Securitized loans [Member] | Residential mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 1,568,446,000
Securitized loans [Member] | Proprietary reverse mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 1,994,473,000
Securitized loans [Member] | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.051
Securitized loans [Member] | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.084
Securitized loans [Member] | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.055
Securitized loans [Member] | Valuation, Market Approach | Residential mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 1,470,667,000
Securitized loans [Member] | Valuation, Market Approach | Residential mortgage loans | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.50
Securitized loans [Member] | Valuation, Market Approach | Residential mortgage loans | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 100.07
Securitized loans [Member] | Valuation, Market Approach | Residential mortgage loans | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 91.36
Securitized loans [Member] | Valuation, Market Approach | Proprietary reverse mortgage loans | Measurement Input, Quoted Price | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 90.06
Securitized loans [Member] | Valuation, Market Approach | Proprietary reverse mortgage loans | Measurement Input, Quoted Price | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 112.17
Securitized loans [Member] | Valuation, Market Approach | Proprietary reverse mortgage loans | Measurement Input, Quoted Price | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 106.91
Securitized loans [Member] | Valuation, Market Approach | Proprietary reverse mortgage loans | Recent transactions  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 175,031,000
Securitized loans [Member] | Valuation, Market Approach | Proprietary reverse mortgage loans | Market quotes  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value 1,819,442,000
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 97,779,000
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.006
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.395
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.065
Non-performing | Valuation, Income Approach | Commercial mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 53,339,000
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 2 months 3 days
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 11 months
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 7 months 15 days
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.092
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.142
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.113
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input recovery amount | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input, Recovery Amount $ 0.800
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input recovery amount | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input, Recovery Amount 1.000
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input recovery amount | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input, Recovery Amount 0.957
Non-performing | Valuation, Income Approach | Residential mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 148,915,000
Non-performing | Valuation, Income Approach | Residential mortgage loans | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 5 months 3 days
Non-performing | Valuation, Income Approach | Residential mortgage loans | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 106 months 24 days
Non-performing | Valuation, Income Approach | Residential mortgage loans | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Investment, measurement input, recovery time 22 months 6 days
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.011
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 1.137
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.077
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input recovery amount | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input, Recovery Amount $ 0.002
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input recovery amount | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input, Recovery Amount 2.643
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input recovery amount | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input, Recovery Amount 0.877
Non-performing securitized residential mortgage loans [Member] | Valuation, Income Approach | Residential mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value 60,800,000
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Fair value $ 243,409,000
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.063
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.122
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.073
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Prepayment Rate | Minimum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.070
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Prepayment Rate | Maximum  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.268
Unsecuritized loans | Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Prepayment Rate | Weighted Average  
Fair Value Measurements Inputs and Valuation Techniques [Line Items]  
Loans, Measurement Input 0.131