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, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Total plan assets	$ 233,075	$ 218,329
Large/mid-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	63,146	46,440
Small-capitalization equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	19,932	17,135
International and emerging market equity securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	24,325	43,079
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	18,008	18,911
Private equity and hedge funds
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	52,027	76,339
Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	5,629	4,509
Total Plan Assets at Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	181,048	141,990
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	40,890	3,076
Contracts with Insurance Companies
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	9,118	8,840
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	160,612	96,486
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	63,146	46,440
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	19,932	17,135
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	24,325	19,117
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	6,690	6,209
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	5,629	4,509
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	40,890	3,076
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Contracts with Insurance Companies
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0	0
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	11,318	36,664
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	0	23,962
Significant Other Observable Inputs (Level 2) \| Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	11,318	12,702
Significant Other Observable Inputs (Level 2) \| Other assets
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0	0
Significant Other Observable Inputs (Level 2) \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0	0
Significant Other Observable Inputs (Level 2) \| Contracts with Insurance Companies
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	9,118	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
Significant Unobservable Inputs (Level 3) \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	0	0
Significant Unobservable Inputs (Level 3) \| Contracts with Insurance Companies
Defined Benefit Plan Disclosure [Line Items]
Total plan assets at fair value	$ 9,118	$ 8,840