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, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cost of goods sold	$ 210,667	$ 195,286	$ 413,856	$ 375,047
Selling, general and administrative	20,946	21,184	42,775	41,133
Beginning of Period			(176,669)	(183,234)
Other comprehensive income (loss) before reclassifications			(9,734)	3,009
Amounts reclassified from accumulated other comprehensive income (loss)			4,862	3,527
Net other comprehensive income (loss) - current period	(9,105)	(420)	(4,872)	6,536
End of Period	(181,541)	(176,698)	(181,541)	(176,698)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	19,269	47,031	42,721	53,152
Income Tax Expense (Benefit)	4,547	2,827	9,834	5,246
Net income	14,722	44,204	32,887	47,906
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period			(86,178)	(93,970)
Other comprehensive income (loss) before reclassifications			(8,905)	2,674
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Net other comprehensive income (loss) - current period			(8,905)	2,674
End of Period	(95,083)	(91,296)	(95,083)	(91,296)
Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period			459	863
Other comprehensive income (loss) before reclassifications			(829)	335
Amounts reclassified from accumulated other comprehensive income (loss)			(361)	(373)
Net other comprehensive income (loss) - current period			(1,190)	(38)
End of Period	(731)	825	(731)	825
Pension & Other Post-retirement Benefit Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning of Period			(90,950)	(90,127)
Other comprehensive income (loss) before reclassifications			0	0
Amounts reclassified from accumulated other comprehensive income (loss)			5,223	3,900
Net other comprehensive income (loss) - current period			5,223	3,900
End of Period	(85,727)	(86,227)	(85,727)	(86,227)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Gain (Loss) on Derivative Financial Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	350	337	556	585
Income Tax Expense (Benefit)	142	125	195	212
Net income	208	212	361	373
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)	(761)	(1,111)	(1,523)	(2,222)
Net income	(2,611)	(1,950)	(5,223)	(3,900)
Amortization Of Prior Service Costs And Net Gains Loss	(3,372)	(3,061)	(6,746)	(6,122)
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	712	321	(944)	(554)
Selling, General and Administrative Expenses [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]
Selling, general and administrative	(378)		(419)
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