Investment in Loans (Schedule of Consumer Loans) (Details) - USD ($) $ in Thousands |
12 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||||||
| Unpaid Principal Balance | $ 1,417,054 | $ 1,387,733 | |||||
| Unamortized Premium (Discount) | (196,118) | (150,821) | |||||
| Investments, at fair value, Cost | $ 2,970,306 | ||||||
| Loans, at fair value | [1],[2] | $ 1,453,480 | $ 1,412,426 | ||||
| Weighted Average | |||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||||||
| Weighted average life | 4 years 5 months 26 days | 5 years 10 months 24 days | |||||
| Consumer loans | |||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||||||
| Fair value of charged-off loans | $ 600 | $ 600 | |||||
| Unpaid Principal Balance | 48,180 | 179,743 | |||||
| Unamortized Premium (Discount) | 72 | 5,027 | |||||
| Investments, at fair value, Cost | 48,252 | 184,770 | |||||
| Gains | 1,160 | 2,561 | |||||
| Losses | (1,887) | (377) | |||||
| Loans, at fair value | $ 47,525 | $ 186,954 | |||||
| Consumer loans | Weighted Average | |||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | |||||||
| Weighted average life | 1 year 14 days | 9 months 25 days | |||||
| Delinquency (Days) | 7 days | 4 days | |||||
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