Pension And Other Post-Retirement Benefits (Schedule Of Components Of Net Periodic Benefit Cost For Pension And Other Post-Retirement Benefit Programs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 58	$ 10	$ 116
Interest cost	2,882	3,164	5,764	6,328
Expected return on plan assets	(3,761)	(3,737)	(7,522)	(7,473)
Amortization of prior service costs, gains or losses and net transition asset	3,428	3,122	6,856	6,245
Net periodic benefit cost	2,554	2,607	5,108	5,216
Other Post-Retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Service cost	10	9	20	18
Interest cost	69	77	138	153
Expected return on plan assets		0
Amortization of prior service costs, gains or losses and net transition asset	(54)	(62)	(108)	(123)
Net periodic benefit cost	$ 25	$ 24	$ 50	$ 48