Goodwill and Intangibles - Schedule of Carrying Value of Goodwill by Reportable Segment Appearing in Accompanying Consolidated Balance Sheets (Details) $ in Thousands	9 Months Ended
Jun. 29, 2018 USD ($)
Goodwill [Roll Forward]
September 29, 2017	$ 3,009,826
Acquired	2,967,100
Post-Acquisition Adjustments	2,800
Foreign Exchange Impact	(24,700)
June 29, 2018	5,955,048
Aerospace, Technology, Environmental and Nuclear
Goodwill [Roll Forward]
September 29, 2017	1,038,200
Acquired	1,090,900
Post-Acquisition Adjustments	2,900
Foreign Exchange Impact	(8,200)
June 29, 2018	2,123,800
Buildings, Infrastructure and Advanced Facilities
Goodwill [Roll Forward]
September 29, 2017	1,048,800
Acquired	1,492,100
Post-Acquisition Adjustments	(100)
Foreign Exchange Impact	(9,500)
June 29, 2018	2,531,300
Energy, Chemicals and Resources
Goodwill [Roll Forward]
September 29, 2017	922,800
Acquired	384,100
Post-Acquisition Adjustments	0
Foreign Exchange Impact	(7,000)
June 29, 2018	$ 1,299,900

Goodwill, Adjustments During Period

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=77989000&loc=SL49117168-202975

+ Details

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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

+ Details

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

+ Details

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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.

+ Details

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