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Financial Instruments (Summary Of Location And Fair Value Of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Net asset (liability)	$ (2,720)	$ (558)
Cost of Goods and Services Sold	849,756	767,550	$ 659,867
Flexible Packaging Films [Member] [Domain]
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	0	0	0
Flexible Packaging Films [Member] [Domain] \| Accrued Expenses
Derivatives, Fair Value [Line Items]
Asset derivatives	(1,053)
Net asset (liability)		(558)
Flexible Packaging Films [Member] [Domain] \| Designated as Hedging Instrument \| Accrued Expenses
Derivatives, Fair Value [Line Items]
Asset derivatives	37	0
Aluminum futures contracts	1,090	558
Flexible Packaging Films [Member] [Domain] \| Not Designated as Hedging Instrument [Member] \| Accrued Expenses
Derivatives, Fair Value [Line Items]
Asset derivatives	0	0
Aluminum futures contracts	0	0
Aluminum Futures Contracts
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(1,123)	1,501	394
Aluminum Futures Contracts \| Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Net asset (liability)	(1,630)
Aluminum Futures Contracts \| Accrued Expenses
Derivatives, Fair Value [Line Items]
Net asset (liability)		562
Aluminum Futures Contracts \| Designated as Hedging Instrument \| Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	20
Aluminum futures contracts	(1,650)
Aluminum Futures Contracts \| Designated as Hedging Instrument \| Accrued Expenses
Derivatives, Fair Value [Line Items]
Asset derivatives		578
Aluminum futures contracts		(16)
Aluminum Futures Contracts \| Not Designated as Hedging Instrument [Member] \| Prepaid Expenses and Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Aluminum futures contracts	0
Aluminum Futures Contracts \| Not Designated as Hedging Instrument [Member] \| Accrued Expenses
Derivatives, Fair Value [Line Items]
Asset derivatives		0
Aluminum futures contracts		0
Selling, General and Administrative Expenses [Member] \| Flexible Packaging Films [Member] [Domain]
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax	(2,105)
Cost of Sales [Member] \| Flexible Packaging Films [Member] [Domain]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	62	62	62
Cost of Sales [Member] \| Aluminum Futures Contracts
Derivatives, Fair Value [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	1,069	1,210	(1,630)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Foreign Currency Forward Contracts
Derivatives, Fair Value [Line Items]
Cost of Goods and Services Sold	(62)	(62)	62
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Aluminum Futures Contracts
Derivatives, Fair Value [Line Items]
Cost of Goods and Services Sold	(1,069)	(1,210)	$ (1,630)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Selling, General and Administrative Expenses [Member] \| Foreign Currency Forward Contracts
Derivatives, Fair Value [Line Items]
Cost of Goods and Services Sold	$ (1,796)	$ (43)