Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|---|---|---|---|
| Credit Default Swap, Selling Protection [Member] | |||
| Credit Derivatives [Line Items] | |||
| Credit Risk Derivatives, at Fair Value, Net | $ 4,339 | ||
| Fair Value | $ 3,171 | $ 5,414 | |
| Notional value | 68,653 | 132,176 | |
| Derivative notional | (98,586) | ||
| Credit Default Swap, Buying Protection [Member] | |||
| Credit Derivatives [Line Items] | |||
| Credit Risk Derivatives, at Fair Value, Net | 284 | ||
| Fair Value of Purchased Credit Derivatives Offsetting Written Credit Derivatives | 0 | (3,248) | |
| Notional value of purchased credit derivatives offsetting written credit derivatives | $ 0 | $ (81,637) | |
| Derivative notional | $ (41,134) |