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Retirement Plans And Other Postretirement Benefits (Schedule Of Pension Plan Assets Categorized By Level Within Fair Value Measurement Hierarchy) (Details) - USD ($) $ in Thousands | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets | $ 218,329 | $ 205,367
Large/mid-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 46,440 | 37,323
Small-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 17,135 | 13,880
International and emerging market equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 43,079 | 32,931
Fixed income securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 18,911 | 17,769
Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount |  | 9,899
Contracts with insurance companies | 8,840 |
Private equity and hedge funds |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 76,339 | 86,786
Other assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 7,585 | 6,779
Total Plan Assets at Fair Value [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 141,990 | 118,581
Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 96,486 | 77,257
Quoted Prices in Active Markets for Identical Assets (Level 1) | Large/mid-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 46,440 | 37,323
Quoted Prices in Active Markets for Identical Assets (Level 1) | Small-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 17,135 | 13,880
Quoted Prices in Active Markets for Identical Assets (Level 1) | International and emerging market equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 19,117 | 13,389
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 6,209 | 5,886
Quoted Prices in Active Markets for Identical Assets (Level 1) | Estimate of Fair Value Measurement [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount |  | 0
Contracts with insurance companies | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 7,585 | 6,779
Significant Other Observable Inputs (Level 2) |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 36,664 | 31,425
Significant Other Observable Inputs (Level 2) | Large/mid-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Other Observable Inputs (Level 2) | Small-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Other Observable Inputs (Level 2) | International and emerging market equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 23,962 | 19,542
Significant Other Observable Inputs (Level 2) | Fixed income securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 12,702 | 11,883
Significant Other Observable Inputs (Level 2) | Other assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Unobservable Inputs (Level 3) |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 8,840 | 9,899
Defined Benefit Plan, Estimated Future Retirement Benefits Covered by Insurance Contract, Amount |  | 9,899
Contracts with insurance companies | 8,840 |
Significant Unobservable Inputs (Level 3) | Large/mid-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Unobservable Inputs (Level 3) | Small-capitalization equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Unobservable Inputs (Level 3) | International and emerging market equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Unobservable Inputs (Level 3) | Fixed income securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | 0 | 0
Significant Unobservable Inputs (Level 3) | Other assets |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Total plan assets at fair value | $ 0 | $ 0

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