Employee Benefits And Deferred Compensation Plans (Schedule Of Target Plan Asset Allocations) (Details) - Pension Plans [Member]	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Weighted average plan asset allocations	100.00%	100.00%
Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average plan asset allocations	67.97%	73.51%
Fixed Income Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average plan asset allocations	30.20%	18.64%
Cash/Short-Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average plan asset allocations	1.83%	7.85%