Investment in Loans (Schedule of Investments in Loans) (Details) - USD ($) $ in Thousands |
Dec. 31, 2020 |
Dec. 31, 2019 |
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|---|---|---|---|---|---|---|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Current Principal/Notional Amount | $ 1,417,054 | $ 1,387,733 | ||||
| Fair Value | [1],[2] | 1,453,480 | 1,412,426 | |||
| Residential mortgage loans | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Current Principal/Notional Amount | 1,150,303 | 911,705 | ||||
| Fair Value | 1,187,069 | 932,203 | ||||
| Commercial mortgage loans | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Current Principal/Notional Amount | 212,716 | 277,870 | ||||
| Fair Value | 213,031 | 274,759 | ||||
| Consumer loans | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Current Principal/Notional Amount | 48,180 | 179,743 | ||||
| Fair Value | 47,525 | 186,954 | ||||
| Corporate loan [Member] | ||||||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||||||
| Current Principal/Notional Amount | 5,855 | 18,415 | ||||
| Fair Value | $ 5,855 | $ 18,510 | ||||
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