Retirement Plans (Schedule Of Weighted Average Actuarial Assumptions Used To Determine Benefit Obligations And Net Periodic Benefit Costs) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Assumptions to determine benefit obligations:
Discount rate	4.07%	4.25%	3.90%
Rate of compensation increase	4.49%	4.49%	4.49%
Assumptions to determine net periodic benefit cost:
Discount rate	4.39%	3.90%	4.80%
Rate of compensation increase	4.49%	4.49%	4.49%
Expected return on plan assets	5.20%	5.22%	5.42%
Postretirement Benefits [Member]
Assumptions to determine benefit obligations:
Discount rate	3.46%	3.63%	3.25%
Assumptions to determine net periodic benefit cost:
Discount rate	3.63%	3.25%	3.65%