Goodwill and intangible Assets Goodwill Rollforward (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Mar. 27, 2015	Oct. 31, 2014
Goodwill [Roll Forward]
Balance at September 26, 2014	$ 277,574us-gaap_Goodwill
Acquired goodwill (preliminary)	40,372us-gaap_GoodwillAcquiredDuringPeriod
Translation adjustments	(5,077)
Balance at March 27, 2015	312,869us-gaap_Goodwill
Doremi Labs [Member]
Goodwill [Roll Forward]
Balance at September 26, 2014		39,672
Acquired goodwill (preliminary)	39,700
Balance at March 27, 2015		39,672
Other Acquisitions [Member]
Goodwill [Roll Forward]
Acquired goodwill (preliminary)	$ 700

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

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- Definition

Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

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-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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Amount of increase (decrease) from foreign currency translation adjustments and purchase accounting adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

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