Accumulated Other Comprehensive Income (Loss) (Schedule Of Reclassifications Of Balances Out Of Accumulated Other Comprehensive Income (Loss) Into Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative	$ 16,767	$ 20,420	$ 55,422	$ 61,654
Income before income taxes	(8,137)	22,918	(47,304)	31,616
Income taxes from continuing operations	(1,908)	5,942	(10,728)	8,308
Net income (loss)	6,203	(65,213)	36,472	(76,339)
Reclassification Out Of Accumulated Other Comprehensive Income | Gain (Loss) on Derivative Financial Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes	(2,141)	2,327	(4,037)	7,079
Income taxes from continuing operations	(476)	496	(880)	1,523
Net income (loss)	1,665	(1,831)	3,157	(5,556)
Reclassification Out Of Accumulated Other Comprehensive Income | Gain (Loss) on Derivative Financial Instruments | Aluminum Futures Contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	2,160	(575)	4,172	(2,766)
Reclassification Out Of Accumulated Other Comprehensive Income | Pension & Other Post-retirement Benefit Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Actuarial gain (loss) and prior service costs, before taxes	(4,244)	(3,767)	(12,727)	(11,300)
Income taxes from continuing operations	927	836	2,773	2,507
Net income (loss)	(3,317)	(2,931)	(9,954)	(8,793)
Selling, general & admin | Reclassification Out Of Accumulated Other Comprehensive Income | Gain (Loss) on Derivative Financial Instruments | Foreign Currency Forward Contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Selling, general and administrative	(34)	(1,767)	(183)	(4,359)
Cost of Sales [Member] | Reclassification Out Of Accumulated Other Comprehensive Income | Gain (Loss) on Derivative Financial Instruments | Foreign Currency Forward Contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of goods sold	$ 15	$ 15	$ 48	$ 46