Valuation (Schedule of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3	12 Months Ended
	Dec. 31, 2018 USD ($)		Dec. 31, 2017	Mar. 31, 2019	Mar. 31, 2019 month	Mar. 31, 2019 $ / shares	Mar. 31, 2019 USD ($)
Corporate equity securities | Non-exchange traded preferred equity investment in loan origination entity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 3,000,000
Valuation, Market Approach | Private label mortgage backed securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 36,945,000						$ 42,096,000
Valuation, Market Approach | Private label mortgage backed securities | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	17.42
Securities, measurement input | $ / shares						15.72
Valuation, Market Approach | Private label mortgage backed securities | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	178.00
Securities, measurement input | $ / shares						184.92
Valuation, Market Approach | Private label mortgage backed securities | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	78.31
Securities, measurement input | $ / shares						82.84
Valuation, Market Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 576,000						5,137,000
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	5.93
Securities, measurement input | $ / shares						5.94
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	6.36
Securities, measurement input | $ / shares						70.90
Valuation, Market Approach | CMBS | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	6.14
Securities, measurement input | $ / shares						60.88
Valuation, Market Approach | Agency interest only RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 744,000						705,000
Valuation, Market Approach | Agency interest only RMBS | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	1.70
Securities, measurement input | $ / shares						8.42
Valuation, Market Approach | Agency interest only RMBS | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	9.12
Securities, measurement input | $ / shares						14.43
Valuation, Market Approach | Agency interest only RMBS | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	5.64
Securities, measurement input | $ / shares						11.96
Valuation, Market Approach | Corporate debt and equity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							1,452,000
Valuation, Market Approach | Corporate debt and equity | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares						83.50
Valuation, Market Approach | Corporate debt and equity | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares						83.50
Valuation, Market Approach | Corporate debt and equity | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input | $ / shares						83.50
Valuation, Market Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 5,828,000						13,508,000
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	2.64
Securities, measurement input | $ / shares						27.30
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	375.00
Securities, measurement input | $ / shares						80.00
Valuation, Market Approach | CLOs | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	167.78
Securities, measurement input | $ / shares						72.87
Valuation, Market Approach | Corporate debt, non-exchange traded corporate equity, and secured notes [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 13,976,000
Valuation, Market Approach | Corporate debt, non-exchange traded corporate equity, and secured notes [Member] | Measurement Input, Quoted Price | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	9.69
Valuation, Market Approach | Corporate debt, non-exchange traded corporate equity, and secured notes [Member] | Measurement Input, Quoted Price | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	91.00
Valuation, Market Approach | Corporate debt, non-exchange traded corporate equity, and secured notes [Member] | Measurement Input, Quoted Price | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	59.18
Valuation, Income Approach | Private label mortgage backed securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 54,346,000						52,574,000
Valuation, Income Approach | Private label mortgage backed securities | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%			100.00%
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	3.50%
Securities, measurement input				0.005
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	66.10%
Securities, measurement input				0.671
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	10.70%
Securities, measurement input				0.095
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	16.00%
Securities, measurement input				0.151
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	92.10%
Securities, measurement input				0.778
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	50.40%
Securities, measurement input				0.466
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	0.00%
Securities, measurement input				0.001
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	23.10%
Securities, measurement input				0.176
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	8.70%
Securities, measurement input				0.088
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	1.50%
Securities, measurement input				0.017
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	14.60%
Securities, measurement input				0.158
Valuation, Income Approach | Private label mortgage backed securities | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	7.30%
Securities, measurement input				0.082
Valuation, Income Approach | Private label mortgage backed securities | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	6.10%
Securities, measurement input				0.163
Valuation, Income Approach | Private label mortgage backed securities | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	61.80%
Securities, measurement input				0.630
Valuation, Income Approach | Private label mortgage backed securities | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	33.60%
Securities, measurement input				0.364
Valuation, Income Approach | CMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 227,000
Valuation, Income Approach | CMBS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral	100.00%
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	3.40%
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	3.40%
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	3.40%
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	2.00%
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	2.00%
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	2.00%
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	6.60%
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	6.60%
Valuation, Income Approach | CMBS | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	6.60%
Valuation, Income Approach | CMBS | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	91.40%
Valuation, Income Approach | CMBS | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	91.40%
Valuation, Income Approach | CMBS | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	91.40%
Valuation, Income Approach | Corporate Debt and non-exchange traded corporate equity [Member]
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 4,793,000
Valuation, Income Approach | Corporate Debt and non-exchange traded corporate equity [Member] | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	17.50%
Valuation, Income Approach | Corporate Debt and non-exchange traded corporate equity [Member] | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	17.50%
Valuation, Income Approach | Corporate Debt and non-exchange traded corporate equity [Member] | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	17.50%
Valuation, Income Approach | Corporate debt and equity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							5,750,000
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.100
Valuation, Income Approach | Corporate debt and equity | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.196
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				0.167
Valuation, Income Approach | Agency interest only RMBS
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 6,549,000						5,684,000
Valuation, Income Approach | Agency interest only RMBS | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	2.11%	[1]	3.81%
Valuation, Income Approach | Agency interest only RMBS | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	35.21%	[1]	35.21%
Valuation, Income Approach | Agency interest only RMBS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	6.77%	[1]	7.30%
Total outstanding collateral	100.00%			100.00%
Valuation, Income Approach | Agency interest only RMBS | Measurement Input, LIBOR OAS | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.0093
Valuation, Income Approach | Agency interest only RMBS | Measurement Input, LIBOR OAS | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.3527
Valuation, Income Approach | Agency interest only RMBS | Measurement Input, LIBOR OAS | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.0654
Valuation, Income Approach | Agency interest only RMBS | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	37.70%
Securities, measurement input				0.300
Valuation, Income Approach | Agency interest only RMBS | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	100.00%
Securities, measurement input				1.000
Valuation, Income Approach | Agency interest only RMBS | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	66.20%
Securities, measurement input				0.677
Valuation, Income Approach | Agency interest only RMBS | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	0.00%
Securities, measurement input				0.000
Valuation, Income Approach | Agency interest only RMBS | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	62.30%
Securities, measurement input				0.700
Valuation, Income Approach | Agency interest only RMBS | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	33.80%
Securities, measurement input				0.323
Valuation, Income Approach | Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							23,303,000
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				0.055
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				0.196
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				0.102
Valuation, Income Approach | CLOs
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 9,087,000						7,930,000
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]
Investment, measurement input, percent	12.60%
Securities, measurement input				0.087
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	103.10%
Securities, measurement input				0.152
Valuation, Income Approach | CLOs | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	26.70%
Securities, measurement input				0.118
Valuation, Income Approach | CLOs | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	8.10%
Securities, measurement input				0.199
Valuation, Income Approach | CLOs | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	88.40%
Securities, measurement input				0.873
Valuation, Income Approach | CLOs | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	65.20%
Securities, measurement input				0.525
Valuation, Income Approach | CLOs | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	3.70%
Securities, measurement input				0.053
Valuation, Income Approach | CLOs | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	40.80%
Securities, measurement input				0.308
Valuation, Income Approach | CLOs | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	13.50%
Securities, measurement input				0.157
Valuation, Income Approach | CLOs | Measurement Input, Projected Collateral Recoveries | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	4.20%
Securities, measurement input				0.042
Valuation, Income Approach | CLOs | Measurement Input, Projected Collateral Recoveries | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	38.00%
Securities, measurement input				0.137
Valuation, Income Approach | CLOs | Measurement Input, Projected Collateral Recoveries | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	11.90%
Securities, measurement input				0.088
Valuation, Income Approach | CLOs | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	3.50%
Securities, measurement input				0.000
Valuation, Income Approach | CLOs | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	13.50%
Securities, measurement input				0.652
Valuation, Income Approach | CLOs | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	9.40%
Securities, measurement input				0.230
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 206,761,000						24,108,000
Valuation, Income Approach | Consumer loans and 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 | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	7.00%
Securities, measurement input				0.120
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	18.30%
Securities, measurement input				0.187
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	8.50%
Securities, measurement input				0.122
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	0.00%
Securities, measurement input				0.000
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	45.90%
Securities, measurement input				0.110
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	33.50%
Securities, measurement input				0.094
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	2.60%
Securities, measurement input				0.016
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	84.80%
Securities, measurement input				0.166
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement Input, Default Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	9.10%
Securities, measurement input				0.149
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	15.20%
Securities, measurement input				0.729
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	96.60%
Securities, measurement input				0.984
Valuation, Income Approach | Consumer loans and asset-backed securities backed by consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	57.40%
Securities, measurement input				0.757
Valuation, Income Approach | Consumer loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							192,115,000
Valuation, Income Approach | Consumer loans | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Total outstanding collateral				100.00%
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.070
Valuation, Income Approach | Consumer loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				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				0.080
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.000
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.554
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.415
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.040
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				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				0.080
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
Valuation, Income Approach | Consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Securities, measurement input				0.857
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				0.505
Valuation, Income Approach | Performing commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 163,876,000
Valuation, Income Approach | Performing commercial mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	8.00%
Valuation, Income Approach | Performing commercial mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	22.50%
Valuation, Income Approach | Performing commercial mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	9.60%
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 80,513,000
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	3 months		4 months
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	16 months		17 months
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	7 months 27 days		9 months 15 days
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	9.60%
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	27.40%
Valuation, Income Approach | Non-performing commercial mortgage loans and commercial real estate owned | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	13.20%
Valuation, Income Approach | Performing residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 171,367,000
Valuation, Income Approach | Performing residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	2.70%
Valuation, Income Approach | Performing residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	12.90%
Valuation, Income Approach | Performing residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	6.00%
Valuation, Income Approach | Securitized residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 314,202,000						296,366,000
Valuation, Income Approach | Securitized residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	4.30%
Loans, measurement input				0.044
Valuation, Income Approach | Securitized residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	4.60%
Loans, measurement input				0.046
Valuation, Income Approach | Securitized residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	4.60%
Loans, measurement input				0.045
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 12,557,000
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	1 month 27 days	[2]	1 month 27 days
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	42 months 6 days	[2]	40 months 15 days
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, recovery time	27 months 24 days	[2]	25 months 18 days
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	4.30%
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	25.10%
Valuation, Income Approach | Non-performing residential mortgage loans and residential real estate owned | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	11.30%
Valuation, Income Approach | Credit default swaps on asset-backed securities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 1,472,000						1,233,000
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]
Investment, measurement input, percent	33.60%
Derivative asset, measurement input				0.341
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Prepayment Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	42.00%
Derivative asset, measurement input				0.386
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]
Investment, measurement input, percent	36.50%
Derivative asset, measurement input				0.360
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Default Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	11.10%
Derivative asset, measurement input				0.117
Valuation, Income Approach | Credit default swaps on asset-backed securities | Measurement Input, Default Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	15.60%
Derivative asset, measurement input				0.181
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]
Investment, measurement input, percent	12.80%
Derivative asset, measurement input				0.133
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]
Investment, measurement input, percent	10.30%
Derivative asset, measurement input				0.142
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]
Investment, measurement input, percent	18.70%
Derivative asset, measurement input				0.175
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]
Investment, measurement input, percent	15.80%
Derivative asset, measurement input				0.162
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]
Investment, measurement input, percent	32.00%
Derivative asset, measurement input				0.291
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]
Investment, measurement input, percent	36.50%
Derivative asset, measurement input				0.365
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]
Investment, measurement input, percent	34.90%
Derivative asset, measurement input				0.345
Valuation, Income Approach | Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 5,192,000
Valuation, Income Approach | Investment in unconsolidated entities | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	12.90%
Valuation, Income Approach | Investment in unconsolidated entities | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	16.10%
Valuation, Income Approach | Investment in unconsolidated entities | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input, percent	15.40%
Valuation, Income Approach | Other secured borrowings, at fair value
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ (297,948,000)						(282,124,000)
Valuation, Income Approach | Other secured borrowings, at fair value | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt, measurement input	3.90%
Debt instrument, measurement input				0.040
Valuation, Income Approach | Other secured borrowings, at fair value | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Debt, measurement input	4.40%
Debt instrument, measurement input				0.041
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, measurement input	4.30%
Debt instrument, measurement input				0.041
Enterprise Value | Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							31,849,000
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				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				3.1
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
Enterprise Value | Corporate equity securities | Non-exchange traded common equity investment in mortgage-related entity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 6,750,000
Enterprise Value | Corporate equity securities | Non-exchange traded common equity investment in mortgage-related entity | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	3.3	[3]	2.0
Enterprise Value | Corporate equity securities | Non-exchange traded common equity investment in mortgage-related entity | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	3.3	[3]	2.0
Enterprise Value | Corporate equity securities | Non-exchange traded common equity investment in mortgage-related entity | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	3.3	[3]	2.0
Enterprise Value | Corporate equity securities | Non-exchange traded preferred equity investment in mortgage-related entity
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value	$ 27,317,000
Enterprise Value | Corporate equity securities | Non-exchange traded preferred equity investment in mortgage-related entity | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	1.1	[3]	0.9
Enterprise Value | Corporate equity securities | Non-exchange traded preferred equity investment in mortgage-related entity | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	1.1	[3]	0.9
Enterprise Value | Corporate equity securities | Non-exchange traded preferred equity investment in mortgage-related entity | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Investment, measurement input	1.1	[3]	0.9
Market Quotes | Investment in unconsolidated entities
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							3,000,000
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				0.041
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				0.226
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				0.060
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							198,823,000
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				0.080
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				0.225
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				0.094
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							274,572,000
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, measurement input				0.043
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, measurement input				0.333
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, measurement input				0.119
Non-performing | Valuation, Income Approach | Commercial mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							40,800,000
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				0.105	0.0
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				0.141	5.0
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				0.128	3.0
Non-performing | Valuation, Income Approach | Residential mortgage loans
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Fair value							$ 12,314,000
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Minimum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, measurement input | month					13.5
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Maximum
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, measurement input | month					62.6
Non-performing | Valuation, Income Approach | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average
Fair Value Measurements Inputs and Valuation Techniques [Line Items]
Loans, measurement input | month					32.3

[1] Shown in basis points.

[2] Excludes certain loans that are re-performing.

[3] Represent an estimation of where market participants might value an enterprise on a price-to-book basis.