Valuation (Schedule of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3 $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares
Total return swaps | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.109	0.085
Derivative Liability, Measurement Input	0.159	0.277
Total return swaps | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.109	0.277
Derivative Liability, Measurement Input	0.159	0.277
Total return swaps | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.109	0.115
Derivative Liability, Measurement Input	0.159	0.277
Valuation, Market Approach | Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 60,935	$ 38,754
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	1.75	6.68
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	291.19	144.79
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	99.35	86.21
Valuation, Market Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 15,245	$ 29,630
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	4.78	5.08
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	59.70	80.72
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	44.50	64.73
Valuation, Market Approach | Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 9,347	$ 3,753
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	0.76	1.36
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	23.12	16.61
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	9.96	5.11
Valuation, Market Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 34,470	$ 38,220
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	20.00	40.00
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	310.00	96.00
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares	67.98	73.98
Valuation, Market Approach | Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 126	$ 139
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	94.80	95.47
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	95.87	96.78
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	95.37	96.12
Valuation, Market Approach | Corporate loan [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 6,114	$ 6,010
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, Income Approach | Non-Agency RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 33,262	$ 50,827
Valuation, Income Approach | Non-Agency RMBS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.016	0.033
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.495	0.609
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.132	0.100
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.006	0.008
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.745	0.720
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.491	0.493
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	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	0.222	0.227
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.063	0.066
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	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	0.277	0.324
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	0.088	0.069
Valuation, Income Approach | Non-Agency RMBS | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.142	0.169
Valuation, Income Approach | Non-Agency RMBS | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.859	0.929
Valuation, Income Approach | Non-Agency RMBS | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.358	0.372
Valuation, Income Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 5,031	$ 175
Valuation, Income Approach | CMBS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.102	0.100
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.318	0.100
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.155	0.100
Valuation, Income Approach | CMBS | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input		1.000
Valuation, Income Approach | CMBS | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input		1.000
Valuation, Income Approach | CMBS | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input		1.000
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	0.002
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.002
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.000
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.018
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.017
Valuation, Income Approach | CMBS | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.980
Valuation, Income Approach | CMBS | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	1.000
Valuation, Income Approach | CMBS | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.981
Valuation, Income Approach | Agency RMBS | Interest only securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 11,634	$ 16,151
Fair Value of Agency IOs, negative OAS measurement input	$ 1,000
Valuation, Income Approach | Agency RMBS | Interest only securities | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
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	0.0318	0.0093
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	0.9325	0.3527
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	0.2263	0.0701
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	0.2007
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.625	0.123
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.940	1.000
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.773	0.723
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.060	0.000
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.375	0.877
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.227	0.277
Valuation, Income Approach | Corporate debt and equity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 1,322	$ 2,507
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.100	0.100
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.100	0.100
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	0.100	0.100
Valuation, Income Approach | Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 25,961	$ 30,458
Valuation, Income Approach | Investment in unconsolidated entities | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Equity method investment, measurement input	0.074	0.037
Valuation, Income Approach | Investment in unconsolidated entities | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Equity method investment, measurement input	0.203	0.148
Valuation, Income Approach | Investment in unconsolidated entities | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Equity method investment, measurement input	0.116	0.099
Valuation, Income Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 9,334	$ 6,759
Valuation, Income Approach | CLOs | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.144	0.140
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.167	0.419
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.150	0.262
Valuation, Income Approach | CLOs | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.635	0.485
Valuation, Income Approach | CLOs | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.635	0.846
Valuation, Income Approach | CLOs | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.635	0.725
Valuation, Income Approach | CLOs | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.248	0.117
Valuation, Income Approach | CLOs | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.248	0.364
Valuation, Income Approach | CLOs | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.248	0.199
Valuation, Income Approach | CLOs | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.110	0.037
Valuation, Income Approach | CLOs | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.110	0.151
Valuation, Income Approach | CLOs | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.110	0.076
Valuation, Income Approach | CLOs | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.007
Valuation, Income Approach | CLOs | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.007
Valuation, Income Approach | CLOs | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.007
Valuation, Income Approach | Asset-backed securities, backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 54,501	$ 48,471
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
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	0.140	0.120
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	0.199	0.202
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	0.140	0.121
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	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	0.099	0.112
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	0.077	0.097
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	0.009	0.006
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	0.202	0.180
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	0.156	0.154
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.703	0.713
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.991	0.994
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.767	0.749
Valuation, Income Approach | Consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 194,803	$ 186,954
Valuation, Income Approach | Consumer loans | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.090	0.070
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.120	0.100
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.101	0.081
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	0.415	0.442
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.140	0.160
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.018	0.030
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.866	0.845
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.106	0.086
Valuation, Income Approach | Consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.134	0.155
Valuation, Income Approach | Consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.982	0.958
Valuation, Income Approach | Consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input	0.754	0.754
Valuation, Income Approach | Corporate loan [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value		$ 12,500
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input		0.150
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input		0.180
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input		0.168
Valuation, Income Approach | Credit default swaps on asset-backed securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 353	$ 993
Valuation, Income Approach | Credit default swaps on asset-backed securities | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%	100.00%
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	0.343	0.354
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	0.430	0.420
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	0.408	0.373
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	0.120	0.042
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	0.150	0.124
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	0.127	0.102
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	0.089	0.100
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	0.165	0.182
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	0.105	0.153
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.356	0.362
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.372	0.415
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Derivative asset, measurement input	0.360	0.372
Valuation, Income Approach | Total return swaps
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 37	$ 620
Fair value	(839)	(436)
Valuation, Income Approach | Other secured borrowings, at fair value
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ (549,668)	$ (594,396)
Valuation, Income 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	0.021	0.029
Valuation, Income 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	0.040
Valuation, Income 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	0.023	0.033
Enterprise Value | Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 39,436	$ 41,392
Enterprise Value | 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	1.0
Enterprise Value | 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	4.0	4.7
Enterprise Value | 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	1.4	1.7
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	0.017	0.016
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	0.209	0.195
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	0.079	0.062
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 292,551	$ 248,214
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	0.070	0.077
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	0.123	0.166
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	0.085	0.088
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 347,346	$ 289,672
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 581,181	$ 628,415
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	0.037	0.032
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	0.041	0.043
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	0.039	0.036
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 4,000	$ 1,500
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.039	0.010
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.246	0.266
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, Measurement Input	0.116	0.091
Non-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 10,749	$ 26,545
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	8 months 25 days	1 month 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	8 months 25 days	23 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	8 months 25 days	11 months 12 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	0.144	0.098
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	0.144	0.147
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	0.144	0.124
Non-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 10,845	$ 14,116
Non-performing | Valuation, Income Approach | Residential mortgage loans | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	0 months	1 month 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	66 months	165 months 12 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	21 months 3 days	54 months 18 days