Goodwill and Intangible Assets Components of Goodwill by Business Segment (Detail) - USD ($) $ in Thousands	6 Months Ended
Mar. 31, 2017	Sep. 30, 2016
Goodwill [Roll Forward]
Gross goodwill, period start	$ 817,096
Less: aggregate impairment charges recorded	(614,958)	$ (614,958)
Goodwill, less accumulated impairments	210,617	202,138
Acquisitions and adjustments	8,479
Gross goodwill, period end	825,575
Brooks Semiconductor Solutions Group
Goodwill [Roll Forward]
Gross goodwill, period start	655,781
Less: aggregate impairment charges recorded	(588,944)	(588,944)
Goodwill, less accumulated impairments	66,789	66,837
Acquisitions and adjustments	(48)
Gross goodwill, period end	655,733
Brooks Life Science Systems
Goodwill [Roll Forward]
Gross goodwill, period start	135,301
Less: aggregate impairment charges recorded	0	0
Goodwill, less accumulated impairments	143,828	135,301
Acquisitions and adjustments	8,527
Gross goodwill, period end	143,828
Other
Goodwill [Roll Forward]
Gross goodwill, period start	26,014
Less: aggregate impairment charges recorded	(26,014)	(26,014)
Goodwill, less accumulated impairments	0	$ 0
Acquisitions and adjustments	0
Gross goodwill, period end	$ 26,014

Goodwill Acquired During Period And Adjustments

No definition available.

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- Definition

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.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=35741047&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

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=64834752&loc=SL49117168-202975

+ Details

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- Definition

Amount before 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.

+ References

+ Details

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- Definition

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

+ References

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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