Valuation (Schedule of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares
Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 155,240,000
Non-Agency RMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.034
Non-Agency RMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.901
Non-Agency RMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.129
Non-Agency RMBS | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.000
Non-Agency RMBS | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	1.000
Non-Agency RMBS | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.384
Non-Agency RMBS | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.000
Non-Agency RMBS | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.871
Non-Agency RMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.114
Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.000
Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.850
Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.104
CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 14,143,000
CMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.062
CMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.191
CMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.156
CMBS | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0
CMBS | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.718
CMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.064
CMBS | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.282
CMBS | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	1.000
CMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.921
CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 20,439,000
CLOs | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.089
CLOs | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.635
CLOs | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.199
Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 5,512,000
Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.235
Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	1.000
Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.633
Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 81,922,000
Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.038
Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.352
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	0.127
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
Asset-backed securities, backed by consumer loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.239
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	0.118
Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.009
Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.511
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	0.277
Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 116,414,000
Valuation, Market Approach | Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 83,002,000
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	0.45
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	187.02
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	77.42
Valuation, Market Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 8,432,000
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	4.82
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	68.00
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	42.75
Valuation, Market Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 14,120,000
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	0.50
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	98.14
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	77.09
Valuation, Market Approach | Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 263,000
Valuation, Market Approach | Agency RMBS | Interest only securities | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	9.68
Valuation, Market Approach | Agency RMBS | Interest only securities | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	9.68
Valuation, Market Approach | Agency RMBS | Interest only securities | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	9.68
Valuation, Market Approach | Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 7,696,000
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	20.50
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	72.28
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	59.87
Valuation, Market Approach | Other secured borrowings, at fair value
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ (1,424,668,000)
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	25.27
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	100.46
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	86.48
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.062
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.097
Valuation, Market Approach | 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	0.070
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.996
Valuation, Market Approach | Other secured borrowings, at fair value | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	1.000
Valuation, Market Approach | 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	1.000
Valuation, Market 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, Market 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, Market 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, Market Approach | Mortgage servicing rights | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.100
Valuation, Market Approach | Mortgage servicing rights | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.371
Valuation, Market Approach | Mortgage servicing rights | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.153
Valuation, Market Approach | Servicing-related asset | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.150
Valuation, Market Approach | Servicing-related asset | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.150
Valuation, Market Approach | Servicing-related asset | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.150
Valuation, Market Approach | Loan commitments | Measurement Input pullthrough rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.642
Valuation, Market Approach | Loan commitments | Measurement Input pullthrough rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	1.000
Valuation, Market Approach | Loan commitments | Measurement Input pullthrough rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.729
Valuation, Market Approach | Loan commitments | measurement input cost to originate loan | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.031
Valuation, Market Approach | Loan commitments | measurement input cost to originate loan | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.065
Valuation, Market Approach | Loan commitments | measurement input cost to originate loan | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Servicing Asset, Measurement Input	0.049
Valuation, Market Approach | HMBS-related obligations
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ (8,423,235,000)
Valuation, Market Approach | HMBS-related obligations | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.020
Valuation, Market 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, Market Approach | HMBS-related obligations | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.043
Valuation, Market Approach | HMBS-related obligations | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.065
Valuation, Market Approach | HMBS-related obligations | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.338
Valuation, Market Approach | HMBS-related obligations | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	0.074
Valuation, Market Approach | Unsecured Borrowings
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ (272,765,000)
Valuation, Market Approach | Unsecured Borrowings | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	75.50
Valuation, Market Approach | Unsecured Borrowings | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	96.52
Valuation, Market Approach | Unsecured Borrowings | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt instrument, measurement input	91.74
Valuation, Income Approach | Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 72,238,000
Valuation, Income Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	5,711,000
Valuation, Income Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	6,319,000
Valuation, Income Approach | Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 5,249,000
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, LIBOR OAS | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.0072
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, LIBOR OAS | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.351
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, LIBOR OAS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.0502
Valuation, Income Approach | Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 74,226,000
Valuation, Income Approach | Corporate debt and equity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 20,335,000
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.078
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.227
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.140
Valuation, Income Approach | Consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 1,759,000
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.088
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.145
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.113
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.000
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.113
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.062
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.000
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.469
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.167
Valuation, Income Approach | Corporate loan [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 5,819,000
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.069
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.372
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.154
Valuation, Income Approach | Credit default swaps on asset-backed securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 8,000
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 asset, 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 asset, 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 asset, 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 asset, 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 asset, 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 asset, 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 asset, 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 asset, 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 asset, measurement input	0.123
Valuation, Income Approach | Total return swaps
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 6,000
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
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
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
Valuation, Income Approach | HECM loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 8,591,912,000
Valuation, Income Approach | HECM loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.022
Valuation, Income Approach | HECM loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.066
Valuation, Income Approach | HECM loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.044
Valuation, Income Approach | HECM loans | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.019
Valuation, Income Approach | HECM loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.338
Valuation, Income Approach | HECM loans | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.074
Valuation, Income Approach | Proprietary reverse mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 329,575,000
Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.073
Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.080
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	0.075
Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.110
Valuation, Income Approach | Proprietary reverse mortgage loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.371
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	0.150
Valuation, Income Approach | Mortgage servicing rights
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 29,580,000
Valuation, Income Approach | Servicing-related asset
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	1,327,000
Valuation, Income Approach | Loan commitments
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	2,584,000
Valuation, Income Approach | HECM buyout loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 17,064,000
Valuation, Income Approach | HECM buyout loans | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	9 days
Valuation, Income Approach | HECM buyout loans | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	60 months
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	0.077
Valuation, Income Approach | HECM buyout loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.141
Valuation, Income Approach | HECM buyout loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.099
Valuation, Income Approach | Forward MSR-related Investments
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 163,336,000
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	0.096
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	0.096
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	0.096
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	0.062
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	0.062
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	0.062
Enterprise Value | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 32,900,000
Value of investments excluded from range calculation	2,900,000
Enterprise Value | Investment in unconsolidated entities | Measurement Input, Net Asset Value
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 82,964,000
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	0.9
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	1.4
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	1.0
Valuation, Cost Approach | Investment in unconsolidated entities | Measurement Input, Exercise Price
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 550,000
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	1.1
Performing and/or Re-performing | Residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.034
Performing and/or Re-performing | Residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.379
Performing and/or Re-performing | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.084
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 233,281,000
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	0.101
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	0.133
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	0.117
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 1,435,663,000
Securitized loans [Member] | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	1,555,368,000
Securitized loans [Member] | Valuation, Market Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 1,446,394,000
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	0.76
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	100.46
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	85.99
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 108,974,000
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
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	0.171
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	0.072
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.003
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.528
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.151
Non-performing | Residential mortgage loans | Measurement Input recovery amount | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input, Recovery Amount	$ 0.410
Non-performing | Residential mortgage loans | Measurement Input recovery amount | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input, Recovery Amount	2.393
Non-performing | Residential mortgage loans | Measurement Input recovery amount | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input, Recovery Amount	1.072
Non-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 33,314,000
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	12 months
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	12 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	12 months
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	0.134
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	0.177
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	0.159
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	$ 0.380
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	1.290
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	0.970
Non-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 102,881,000
Non-performing | Valuation, Income Approach | Residential mortgage loans | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	7 months
Non-performing | Valuation, Income Approach | Residential mortgage loans | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	87 months 18 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	20 months 15 days
Non-performing securitized residential mortgage loans [Member] | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 16,600,000