Derivative Financial Instruments (Summary Of Location And Fair Value Of Derivative Financial Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Flexible Packaging Films [Member] [Domain] \| Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ (468)	$ 387
Aluminum Futures Contracts \| Prepaid Expenses and Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative Assets (Liabilities), at Fair Value, Net	2,413	1,538
Derivatives Designated As Hedging Instruments [Member] \| Flexible Packaging Films [Member] [Domain] \| Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	853
Liability derivatives: Fair Value	468	466
Derivatives Designated As Hedging Instruments [Member] \| Aluminum Futures Contracts \| Accrued Expenses [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2,413	1,560
Liability derivatives: Fair Value	$ 0	$ (22)

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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-Publisher FASB
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-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=117331979&loc=d3e41228-113958

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- Definition

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

+ References

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- Definition

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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