Composition Of Certain Financial Statement Captions (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 26, 2021	Mar. 26, 2021	Sep. 25, 2020
Composition Of Certain Financial Statement Captions [Line Items]
Raw materials	$ 3,517	$ 3,517	$ 3,770
Other Noncurrent Assets [Member]
Composition Of Certain Financial Statement Captions [Line Items]
Raw materials	2,100	$ 2,100	2,600
Land and Building [Member] \| Other Current Assets [Member]
Composition Of Certain Financial Statement Captions [Line Items]
Land and building held for sale			$ 2,200
Gain on sale of property	$ 13,900
Percent of property owned by our controlling interest and percent of gain recognized attributed to our controlling interest		51.00%

Composition Of Certain Financial Statement Captions [Line Items].

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- Definition

Property, Plant, And Equipment, Percent Owned By Controlling Interest

+ References

No definition available.

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- Definition

Amount of assets held-for-sale that are not part of a disposal group.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 15
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=121558832&loc=d3e400-110220

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- Definition

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

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- Definition

Amount before valuation and LIFO reserves of raw materials expected to be sold, or consumed within one year or operating cycle, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.6(a)(4))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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