Retirement Plans (Schedule Of Allocation Of Plan Assets) (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	100.00%	100.00%
Weighted Average Expected Long-term Rates of Return	5.50%	5.50%	6.00%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted Average Expected Long-term Rates of Return	4.20%	4.50%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted Average Expected Long-term Rates of Return	5.60%	5.50%
Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	0.20%	0.20%
Cash Equivalents [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	0.00%	0.00%
Cash Equivalents [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	1.00%	1.00%
Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	18.10%	20.10%
Equity Mutual Funds [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	15.00%	15.00%
Weighted Average Expected Long-term Rates of Return	5.90%	6.20%
Equity Mutual Funds [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	25.00%	25.00%
Weighted Average Expected Long-term Rates of Return	8.30%	8.40%
Fixed Income Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	81.70%	79.70%
Fixed Income Mutual Funds [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	75.00%	75.00%
Weighted Average Expected Long-term Rates of Return	3.80%	3.40%
Fixed Income Mutual Funds [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	85.00%	85.00%
Weighted Average Expected Long-term Rates of Return	5.00%	4.40%