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Valuation (Schedule of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3
 6 Months Ended 12 Months Ended
Jun. 30, 2019
USD ($)
$ / shares
Dec. 31, 2018
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 | Non-Agency RMBS    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 40,642,000 $ 36,945,000
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input   17.42
Securities, measurement input | $ / shares 65.77  
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input   178.00
Securities, measurement input | $ / shares 163.50  
Valuation, Market Approach | Non-Agency RMBS | Measurement Input, Quoted Price | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input   78.31
Securities, measurement input | $ / shares 84.87  
Valuation, Market Approach | CMBS    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 5,201,000 $ 576,000
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 5.87  
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 79.27  
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 67.48  
Valuation, Market Approach | Agency RMBS | Interest only securities    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 935,000 $ 744,000
Valuation, Market Approach | Agency RMBS | Interest only securities | Measurement Input, Quoted Price | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input   1.70
Securities, measurement input | $ / shares 1.84  
Valuation, Market Approach | Agency RMBS | Interest only securities | Measurement Input, Quoted Price | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input   9.12
Securities, measurement input | $ / shares 17.07  
Valuation, Market Approach | Agency RMBS | Interest only securities | Measurement Input, Quoted Price | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input   5.64
Securities, measurement input | $ / shares 7.42  
Valuation, Market Approach | Investment in unconsolidated entities    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 3,000,000  
Valuation, Market Approach | CLOs    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 9,174,000 $ 5,828,000
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 27.65  
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 276.53  
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 73.75  
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, Market Approach | Total return swaps    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 87,000  
Valuation, Market Approach | Total return swaps | Measurement Input, Quoted Price | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Derivative asset, measurement input 89.50  
Valuation, Market Approach | Total return swaps | Measurement Input, Quoted Price | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Derivative asset, measurement input 89.88  
Valuation, Market Approach | Total return swaps | Measurement Input, Quoted Price | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Derivative asset, measurement input 89.7  
Valuation, Income Approach | Non-Agency RMBS    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 56,148,000 $ 54,346,000
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]    
Investment, measurement input, percent   3.50%
Securities, measurement input 0.004  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   66.10%
Securities, measurement input 0.277  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Discount Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   10.70%
Securities, measurement input 0.100  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   16.00%
Securities, measurement input 0.059  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   92.10%
Securities, measurement input 0.715  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Prepayment Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   50.40%
Securities, measurement input 0.515  
Valuation, Income Approach | Non-Agency RMBS | 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 | Non-Agency RMBS | Measurement Input, Default Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   23.10%
Securities, measurement input 0.149  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Default Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   8.70%
Securities, measurement input 0.071  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   1.50%
Securities, measurement input 0.015  
Valuation, Income Approach | Non-Agency RMBS | Measurement Input, Projected Collateral Recoveries | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   14.60%
Securities, measurement input 0.183  
Valuation, Income Approach | Non-Agency RMBS | 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 0.095  
Valuation, Income Approach | Non-Agency RMBS | 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 0.178  
Valuation, Income Approach | Non-Agency RMBS | 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 0.778  
Valuation, Income Approach | Non-Agency RMBS | 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 0.319  
Valuation, Income Approach | CMBS    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 1,077,000 $ 227,000
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]    
Investment, measurement input, percent   3.40%
Securities, measurement input 0.215  
Valuation, Income Approach | CMBS | Measurement Input, Discount Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   3.40%
Securities, measurement input 0.215  
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%
Securities, measurement input 0.215  
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   2.00%
Securities, measurement input 0.011  
Valuation, Income Approach | CMBS | Measurement Input, Default Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   2.00%
Securities, measurement input 0.011  
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%
Securities, measurement input 0.011  
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%
Securities, measurement input 0.023  
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%
Securities, measurement input 0.023  
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%
Securities, measurement input 0.023  
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%
Securities, measurement input 0.966  
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%
Securities, measurement input 0.966  
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%
Securities, measurement input 0.966  
Valuation, Income Approach | Agency RMBS | Interest only securities    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 10,099,000 $ 6,549,000
Valuation, Income Approach | Agency RMBS | Interest only securities | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   2.11%
Valuation, Income Approach | Agency RMBS | Interest only securities | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   35.21%
Valuation, Income Approach | Agency RMBS | Interest only securities | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   6.77%
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 0.0093  
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 0.3527  
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 0.0581  
Valuation, Income Approach | Agency RMBS | Interest only securities | Measurement Input, Prepayment Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   37.70%
Securities, measurement input 0.291  
Valuation, Income Approach | Agency RMBS | Interest only securities | 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 RMBS | Interest only securities | Measurement Input, Prepayment Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, percent   66.20%
Securities, measurement input 0.719  
Valuation, Income Approach | Agency RMBS | Interest only securities | 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 RMBS | Interest only securities | 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 0.709  
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]    
Investment, measurement input, percent   33.80%
Securities, measurement input 0.281  
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 $ 5,872,000  
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 0.229  
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 0.189  
Valuation, Income Approach | Investment in unconsolidated entities    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 34,088,000  
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 0.031  
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 0.156  
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 0.091  
Valuation, Income Approach | CLOs    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 8,048,000 $ 9,087,000
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 0.112  
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 0.607  
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 0.130  
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 0.090  
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 0.871  
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 0.496  
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 0.029  
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 0.334  
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 0.150  
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 0.038  
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 0.130  
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 0.773  
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 0.266  
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
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%
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%
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%
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%
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%
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%
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%
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%
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%
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%
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%
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%
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%
Valuation, Income Approach | Asset-backed securities, backed by consumer loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 25,019,000  
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%  
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 0.120  
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 0.201  
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 0.122  
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Prepayment Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.000  
Valuation, Income Approach | Asset-backed securities, backed by consumer loans | Measurement Input, Prepayment Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.108  
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 0.093  
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 0.008  
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 0.360  
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 0.150  
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 0.640  
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 0.992  
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 0.757  
Valuation, Income Approach | Consumer loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 162,609,000  
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 0.567  
Valuation, Income Approach | Consumer loans | Measurement Input, Prepayment Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.425  
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.019  
Valuation, Income Approach | Consumer loans | Measurement Input, Default Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.863  
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 0.137  
Valuation, Income Approach | Consumer loans | Measurement input, Projected Collateral Scheduled Amortization | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.981  
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 0.495  
Valuation, Income Approach | Corporate loan [Member]    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 5,000,000  
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 0.150  
Valuation, Income Approach | Corporate loan [Member] | Measurement Input, Discount Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Securities, measurement input 0.150  
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
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
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
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
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%
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%
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%
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
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
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
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 $ 1,090,000 $ 1,472,000
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 0.346  
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 0.444  
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 0.376  
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 0.114  
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 0.187  
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 0.137  
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 0.137  
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 0.181  
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]    
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 0.234  
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 0.361  
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 0.325  
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 $ (475,816,000) $ (297,948,000)
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 0.031  
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 0.045  
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 0.038  
Enterprise Value | Investment in unconsolidated entities    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 32,588,000  
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
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
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
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
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
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
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 0.039  
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 0.293  
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 0.065  
Performing and/or Re-performing | Valuation, Income Approach | Commercial mortgage loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 206,710,000  
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 0.079  
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 0.120  
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 0.088  
Performing and/or Re-performing | Valuation, Income Approach | Residential mortgage loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 147,108,000  
Securitized loans [Member] | Valuation, Income Approach | Residential mortgage loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 503,090,000  
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 0.038  
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 0.051  
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 0.044  
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Loans, Measurement Input 0.036  
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Loans, Measurement Input 0.560  
Non-performing | Residential mortgage loans | Measurement Input, Discount Rate | Weighted Average    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Loans, Measurement Input 0.123  
Non-performing | Valuation, Income Approach | Commercial mortgage loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 53,324,000  
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, recovery time 2 months  
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, recovery time 6 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 3 months  
Non-performing | Valuation, Income Approach | Commercial mortgage loans | Measurement Input, Discount Rate | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Loans, Measurement Input 0.108  
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 0.254  
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 0.155  
Non-performing | Valuation, Income Approach | Residential mortgage loans    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Fair value $ 13,682,000  
Non-performing | Valuation, Income Approach | Residential mortgage loans | Minimum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, recovery time 0 days  
Non-performing | Valuation, Income Approach | Residential mortgage loans | Maximum    
Fair Value Measurements Inputs and Valuation Techniques [Line Items]    
Investment, measurement input, recovery time 102 months 22 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 45 months 22 days