Pension Plans And Other Post-Retirement Benefits (Schedule Of Net Liability Recognized On Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Current liability	$ 403	$ 267
Noncurrent liability	43,517	42,690
Net liability recognized	43,920	42,957
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liability	25,531	24,021
Net liability recognized	$ 25,531	$ 24,021