| **Pension Plans And Other Post-Retirement Benefits (Schedule Of Net Liability Recognized On Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands** | Dec. 31, 2019 | Dec. 31, 2018 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| Pension Benefits [Member]                                                                                                                                     |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                              |          |          |
| Current liability                                                                                                                                             | $ 403         | $ 267         |
| Noncurrent liability                                                                                                                                          | 43,517        | 42,690        |
| Net liability recognized                                                                                                                                      | 43,920        | 42,957        |
| Other Postretirement Benefits [Member]                                                                                                                        |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                                              |          |          |
| Noncurrent liability                                                                                                                                          | 25,531        | 24,021        |
| Net liability recognized                                                                                                                                      | $ 25,531      | $ 24,021      |

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Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as current.
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| - Definition
Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans.
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| - Definition
Amount of liability, recognized in statement of financial position, for defined benefit pension and other postretirement plans, classified as noncurrent.
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