Investment in Loans Investment in Loans (Schedule of Residential Mortgage Loans: Performance) (Details) - USD ($) $ in Thousands |
Dec. 31, 2020 |
Dec. 31, 2019 |
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|---|---|---|---|---|---|---|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Unpaid Principal Balance | $ 1,417,054 | $ 1,387,733 | ||||
| Loans, at fair value | [1],[2] | 1,453,480 | 1,412,426 | |||
| Residential mortgage loans | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Unpaid Principal Balance | 1,150,303 | 911,705 | ||||
| Loans, at fair value | 1,187,069 | 932,203 | ||||
| Residential mortgage loans | Performing Financial Instruments [Member] | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Unpaid Principal Balance | 18,120 | 27,663 | ||||
| Loans, at fair value | 16,741 | 25,323 | ||||
| Residential mortgage loans | Non-performing | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Unpaid Principal Balance | 62,009 | 17,757 | ||||
| Loans, at fair value | $ 58,169 | $ 15,580 | ||||
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