Valuation (Schedule of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3	12 Months Ended
	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($) $ / shares
Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 134,888,000	$ 127,838,000
Fair Value of Level 3 Assets, Negative Yield	$ 2,100,000	$ 300,000
Non-Agency RMBS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair Value Inputs, Yield Including Negative	6.50%	7.30%
Non-Agency RMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0	0.007
Non-Agency RMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.386	0.526
Non-Agency RMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.068	0.074
Non-Agency RMBS | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0	0
Non-Agency RMBS | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.744	0.991
Non-Agency RMBS | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.391	0.453
Non-Agency RMBS | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0	0.004
Non-Agency RMBS | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.829	0.726
Non-Agency RMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.225	0.184
Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0	0
Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.915	0.791
Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.175	0.168
CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 13,134,000	$ 63,148,000
CMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.076	0.037
CMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.263	0.263
CMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.103	0.087
CMBS | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0	0.007
CMBS | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.065	0.107
CMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.023	0.036
CMBS | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.100	0.724
CMBS | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	1.000	0.961
CMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.950	0.906
CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 26,678,000	$ 111,100,000
Fair Value of Level 3 Assets, Negative Yield	$ 14,000
CLOs | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair Value Inputs, Yield Including Negative	32.70%
CLOs | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.090	0.034
CLOs | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	2.921	0.354
CLOs | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.328	0.105
CLOs | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.134	0.412
CLOs | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.945	0.977
CLOs | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.913	0.657
CLOs | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.019	0.017
CLOs | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.689	0.289
CLOs | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.044	0.112
CLOs | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.013	0.006
CLOs | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.178	0.152
CLOs | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.034	0.079
Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 9,710,000	$ 11,663,000
Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.495	0.083
Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	1.000	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	0.788	0.759
Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value		$ 44,925,000
Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.095	0.126
Asset-backed securities, backed by consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.228	0.275
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	0.157	0.156
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	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	0.116	0.116
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	0.090	0.077
Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.010	0.010
Asset-backed securities, backed by consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.311	0.211
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	0.209	0.171
Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 195,643,000	$ 141,620,000
Corporate loan [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	10,531,000
Corporate loan [Member] | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input		0.211
Corporate loan [Member] | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input		0.211
Corporate loan [Member] | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input		0.211
Total return swaps | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input		0.220
Derivative Liability, Measurement Input		0.168
Total return swaps | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input		0.220
Derivative Liability, Measurement Input		0.168
Total return swaps | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input		0.220
Derivative Liability, Measurement Input		0.168
Valuation, Market Approach | Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 89,344,000	$ 70,619,000
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	0.34	9.53
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	222.87	204.61
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	85.17	85.70
Valuation, Market Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 12,866,000	$ 53,199,000
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	7.00	4.79
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	90.77	98.00
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	56.98	65.20
Valuation, Market Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 18,664,000	$ 102,910,000
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	14.00	2.00
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	99.75	330.00
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	54.99	88.66
Valuation, Market Approach | Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 3,558,000	$ 4,844,000
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	0.72	1.91
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	20.36	18.91
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	7.31	8.38
Valuation, Market Approach | Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value		$ 97,000
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		96.51
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		98.43
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		97.33
Valuation, Market Approach | Corporate loan [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 7,000,000	$ 5,855,000
Valuation, Market Approach | Corporate loan [Member] | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	100.00	100.00
Valuation, Market Approach | Corporate loan [Member] | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	100.00	100.00
Valuation, Market Approach | Corporate loan [Member] | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	100.00	100.00
Valuation, Market Approach | Other secured borrowings, at fair value
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ (984,168,000)	$ (754,921,000)
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	93.34	85.37
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	102.14	105.61
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	99.94	102.04
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	0.018	0.016
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	0.025	0.030
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	0.021	0.026
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	0
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	0.972	0.753
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	0.681	0.487
Valuation, Income Approach | Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 45,544,000	$ 57,219,000
Valuation, Income Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	268,000	9,949,000
Valuation, Income Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	8,014,000	8,190,000
Valuation, Income Approach | Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	6,152,000	6,819,000
Fair Value of Agency IOs, negative OAS measurement input	$ 2,100,000	$ 4,500,000
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	0.0135	0.0297
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	1.9247	0.2886
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	0.0683	0.0914
Valuation, Income Approach | Agency RMBS | Interest only securities | Net LIBOR OAS [Member] | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.0485	0.0396
Valuation, Income Approach | Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 73,108,000	$ 44,828,000
Valuation, Income Approach | Corporate debt and equity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 12,754,000	$ 5,672,000
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.081	0.081
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.443	0.108
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	0.147	0.097
Valuation, Income Approach | Consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 62,365,000	$ 47,525,000
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.052	0.078
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.756	0.281
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.093	0.112
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.000	0.000
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.284	0.360
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.141	0.173
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.009	0.009
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.866	0.866
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.097	0.094
Valuation, Income Approach | Corporate loan [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 3,531,000
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.030
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.219
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.161
Valuation, Income Approach | Credit default swaps on asset-backed securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 303,000	$ 347,000
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	0.339	0.327
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	0.419	0.397
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	0.401	0.381
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	0.065	0.066
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	0.088	0.108
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	0.070	0.089
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	0.112	0.139
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	0.114	0.181
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	0.113	0.156
Valuation, Income Approach | Total return swaps
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value		$ 9,000
Fair value		(484,000)
Enterprise Value | Investment in unconsolidated entities | Measurement Input, Equity Price-to-Book
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 123,779,000	79,536,000
Enterprise Value | Investment in unconsolidated entities | Measurement Input, Net Asset Value
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 57,828,000	$ 62,084,000
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	1.2	1.0
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	1.9	6.2
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	1.5	1.4
Performing and/or Re-performing | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 952,656,000	$ 353,924,000
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	0.009	0.025
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	0.575	0.285
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	0.047	0.054
Performing and/or Re-performing | Residential mortgage loans | Measurement Input, Offered Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input		60.00
Performing and/or Re-performing | Residential mortgage loans | Measurement Input, Offered Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input		103.88
Performing and/or Re-performing | Residential mortgage loans | Measurement Input, Offered Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input		103.44
Performing and/or Re-performing | Valuation, Market Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value		$ 15,659,000
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 310,735,000	$ 181,545,000
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	0.051	0.037
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	0.106	0.097
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	0.072	0.081
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 951,723,000	$ 338,265,000
Securitized loans [Member] | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	1,041,545,000	801,343,000
Securitized loans [Member] | Valuation, Market Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 1,003,164,000	$ 783,162,000
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	88.36	5.34
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	102.14	105.61
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	99.83	100.22
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 38,381,000	$ 18,182,000
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	0.013	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	0.235	0.387
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	0.042	0.044
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.008	0.012
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.359	0.410
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.115	0.121
Non-performing | Residential mortgage loans | Measurement Input recovery amount | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input, Recovery Amount	$ 0.005	$ 0.009
Non-performing | Residential mortgage loans | Measurement Input recovery amount | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input, Recovery Amount	1.748	17.130
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	0.348	0.306
Non-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 15,462,000	$ 31,486,000
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	1 month 24 days	1 month 24 days
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	1 month 24 days	5 months 24 days
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	1 month 24 days	3 months 21 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	0.106	0.086
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	0.106	0.146
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	0.106	0.108
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	$ 1.002	$ 1.000
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	1.002	1.024
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	1.002	1.008
Non-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 22,027,000	$ 31,802,000
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 24 days	0 months
Non-performing | Valuation, Income Approach | Residential mortgage loans | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	100 months 24 days	106 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	29 months 15 days	30 months
Non-performing securitized residential mortgage loans [Member] | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 8,800,000	$ 26,400,000