Employee Benefit Plans (Other Changes In Plan Assets And Benefit Obligations Recognized In Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in AOCL [Roll Forward]
Accumulated Other Comprehensive Income, Beginning Balance	$ (120,491)
Net actuarial loss	(27,351)	$ (2,323)	$ (46,008)
Amortization of prior service credit	(181)	(181)	(181)
Amortization of actuarial loss	5,820	10,352	6,371
Settlement cost	2,606	1,964	2,460
Total other comprehensive loss	(41,586)	17,087	(36,337)
Accumulated Other Comprehensive Income, Ending Balance	(162,077)	(120,491)
Pension Plan [Member]
Changes in AOCL [Roll Forward]
Accumulated Other Comprehensive Income, Beginning Balance	(88,602)	(97,226)	(58,584)
Net actuarial loss	(24,051)	(2,922)	(46,543)
Amortization of prior service credit	(181)	(181)	(181)
Amortization of actuarial loss	5,489	9,763	5,622
Settlement cost	2,606	1,964	2,460
Total other comprehensive loss	(16,137)	8,624	(38,642)
Accumulated Other Comprehensive Income, Ending Balance	(104,739)	(88,602)	(97,226)
Other Postretirement Benefits [Member]
Changes in AOCL [Roll Forward]
Accumulated Other Comprehensive Income, Beginning Balance	(5,409)	(6,597)	(7,881)
Net actuarial loss	(3,300)	599	535
Amortization of prior service credit	0	0	0
Amortization of actuarial loss	331	589	749
Settlement cost	0	0	0
Total other comprehensive loss	(2,969)	1,188	1,284
Accumulated Other Comprehensive Income, Ending Balance	$ (8,378)	$ (5,409)	$ (6,597)

Changes in AOCL [Roll Forward]

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Amount, after tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, after tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount, after tax and reclassification adjustment, of (increase) decrease in accumulated other comprehensive income for defined benefit plan.

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Amount, after tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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