Financial Instruments (Schedule Of Pretax Effect On Net Income (Loss) And Other Comprehensive Income (Loss) Of Derivative Instruments Classified As Cash Flow Hedges) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Aluminum Futures Contracts [Member]
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	$ (4,525)	$ 6,215	$ 74
Flexible Packaging Films
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	0	0	0
Cost of Sales [Member] | Aluminum Futures Contracts [Member]
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	1,022	5,787	(2,717)
Cost of Sales [Member] | Flexible Packaging Films
Derivatives, Fair Value [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	61	63	62
Selling, General and Administrative Expenses [Member] | Flexible Packaging Films
Derivatives, Fair Value [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	3,269	(2,415)	(4,437)
Selling, General and Administrative Expenses [Member] | Foreign Currency Forward Contracts | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ 1,378	$ (337)	$ (6,069)