Accrued Expenses (Schedule Of Accrued Expenses) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Liabilities [Abstract]
Accrued Environmental Loss Contingencies, Current	$ 2,066	$ 2,122
Vacation	7,283	6,975
Payrolls, related taxes and medical and other benefits	9,571	6,227
Incentive compensation	8,138	9,603
Workers’ compensation and disabilities	2,986	3,546
Accrued Utilities, Current	1,460	1,711
Accrued Customer Rebates	1,398	1,504
Other	4,061	3,020
Accrued expenses	40,741	39,465
Accrued Severance Liability	1,894	1,180
Accrued Freight	1,397	1,389
Derivative Assets (Liabilities), at Fair Value, Net	$ 487	$ 2,188