Goodwill and intangible Assets Finite-Lived Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Mar. 27, 2015	Mar. 28, 2014	Sep. 26, 2014
Finite-Lived Intangible Assets [Line Items]
Cost	$ 221,044		$ 168,673
Accumulated Amortization	(114,675)		(104,973)
Total	106,369us-gaap_FiniteLivedIntangibleAssetsNet		63,700us-gaap_FiniteLivedIntangibleAssetsNet
Purchases of intangible assets	(6,416)	(12,400)
Acquired Patents And Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	142,215		99,262
Accumulated Amortization	(68,063)		(61,678)
Total	74,152		37,584
Purchases of intangible assets	(6,400)
Weighted average useful life	18 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	56,912		30,717
Accumulated Amortization	(25,357)		(22,739)
Total	31,555		7,978
Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Cost	21,917		38,694
Accumulated Amortization	(21,255)		(20,556)
Total	$ 662		$ 18,138

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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