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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (169,190)	$ (206,309)	$ (169,190)	$ (206,309)	$ (178,404)	$ (197,651)
Selling, general and administrative	20,275	21,190	38,659	41,234
Income before income taxes	(26,451)	(18,192)	(39,166)	8,698
Income taxes from continuing operations	(5,723)	(3,860)	(8,820)	2,366
Net income (loss)	21,236	11,196	30,267	(11,126)
Foreign Currency Translation
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(82,804)	(112,666)	(82,804)	(112,666)	(84,149)	(100,663)
Gain (Loss) on Derivative Financial Instruments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	3,496	(3,824)	3,496	(3,824)	2,264	(1,307)
Pension & Other Post-retirement Benefit Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(89,882)	(89,819)	(89,882)	(89,819)	$ (96,519)	$ (95,681)
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	(1,241)	3,333	(1,896)	4,752
Income taxes from continuing operations	(257)	721	(404)	1,027
Net income (loss)	984	(2,612)	1,492	(3,725)
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	1,372	(1,551)	2,012	(2,191)
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	(4,240)	(3,766)	(8,483)	(7,533)
Income taxes from continuing operations	922	835	1,846	1,671
Net income (loss)	(3,318)	(2,931)	(6,637)	(5,862)
Selling, General and Administrative Expenses [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]
Selling, general and administrative	(147)	(1,798)	(149)	(2,592)
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	$ 16	$ 16	$ 33	$ 31