Accumulated Other Comprehensive Income (Loss) (Schedule Of After-Tax Changes In Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Selling, general and administrative	$ 25,212	$ 23,864	$ 48,381	$ 45,875
Beginning of Period			(197,651)	(179,987)
Other comprehensive income (loss) before reclassifications			(18,245)	(1,501)
Amounts reclassified from accumulated other comprehensive income (loss)			9,587	5,644
Net other comprehensive income (loss) - current period	3,715	3,207	(8,658)	4,143
End of Period	(206,309)	(175,844)	(206,309)	(175,844)
Income (loss) before income taxes	14,260	18,917	(14,603)	42,728
Income Tax Expense (Benefit)	3,064	4,440	(3,477)	8,467
Net income (loss)	11,196	14,477	(11,126)	34,261
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period			(100,663)	(96,940)
Other comprehensive income (loss) before reclassifications			(12,003)	(283)
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Net other comprehensive income (loss) - current period			(12,003)	(283)
End of Period	(112,666)	(97,223)	(112,666)	(97,223)
Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period			(1,307)	(1,601)
Other comprehensive income (loss) before reclassifications			(6,242)	(1,218)
Amounts reclassified from accumulated other comprehensive income (loss)			3,725	1,486
Net other comprehensive income (loss) - current period			(2,517)	268
End of Period	(3,824)	(1,333)	(3,824)	(1,333)
Pension & Other Post-retirement Benefit Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period			(95,681)	(81,446)
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive income (loss)			5,862	4,158
Net other comprehensive income (loss) - current period			5,862	4,158
End of Period	(89,819)	(77,288)	(89,819)	(77,288)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income (loss) before income taxes	(3,333)	(959)	(4,752)	(1,752)
Income Tax Expense (Benefit)	(721)	(131)	(1,027)	(266)
Net income (loss)	(2,612)	(828)	(3,725)	(1,486)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Pension & Other Post-retirement Benefit Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income Tax Expense (Benefit)	(835)	(593)	(1,671)	(1,185)
Net income (loss)	(2,931)	(2,079)	(5,862)	(4,158)
Amortization Of Prior Service Costs And Net Gains Loss	(3,766)	(2,672)	(7,533)	(5,343)
Aluminum Futures Contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of goods sold	(1,551)	(606)	(2,191)	(1,223)
Cost of Sales [Member] | Foreign Currency Forward Contracts [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of goods sold	$ 16	$ 16	$ 31	$ 31