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Business Acquisitions, Goodwill and Intangible Assets - Goodwill (Details) - USD ($) $ in Thousands | 12 Months Ended
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Sep. 30, 2019 | Sep. 30, 2018
Changes in the carrying value of goodwill by reporting segment |  |
Goodwill at the beginning of the period | $ 5,921,116 | $ 5,992,900
Measurement Period Adjustment |  | 91,000
Impairment | (588,000) | (125,400)
Disposal | (18,300) |
Foreign Exchange Impact | (39,500) | (37,400)
Goodwill at the end of the period | 5,275,281 | 5,921,116
Design and Consulting Services |  |
Changes in the carrying value of goodwill by reporting segment |  |
Goodwill at the beginning of the period | 3,189,200 | 3,218,900
Disposal | (5,800) |
Foreign Exchange Impact | (22,200) | (29,700)
Goodwill at the end of the period | 3,161,200 | 3,189,200
Construction Services |  |
Changes in the carrying value of goodwill by reporting segment |  |
Goodwill at the beginning of the period | 1,008,900 | 1,049,900
Measurement Period Adjustment |  | 91,000
Impairment | (588,000) | (125,400)
Foreign Exchange Impact | (3,300) | (6,600)
Goodwill at the end of the period | 417,600 | 1,008,900
Management Services |  |
Changes in the carrying value of goodwill by reporting segment |  |
Goodwill at the beginning of the period | 1,723,000 | 1,724,100
Disposal | (12,500) |
Foreign Exchange Impact | (14,000) | (1,100)
Goodwill at the end of the period | $ 1,696,500 | $ 1,723,000

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- Definition The amount of an adjustment to a previously reported goodwill impairment charge, which will be recognized in the subsequent reporting period. + References No definition available. + Details
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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://fasb.org/us-gaap/role/ref/legacyRef -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 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + 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 Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 + Details
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- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13854-109267 Reference 2: 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=118932676&loc=d3e3602-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13777-109266 + Details
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