Financial Derivatives (Schedule of Credit Derivatives) (Details) - USD ($) $ in Thousands |
Sep. 30, 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 | $ 4,718 | |
| Notional value | 134,377 | |
| 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 | (2,581) | |
| Notional value of purchased credit derivatives offsetting written credit derivatives | $ (84,029) | |
| Derivative notional | $ (41,134) |