XML 41 R35.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Basis of Presentation (Details) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2015 segment | Mar. 31, 2015 segment
Number of reportable segments | 3 us-gaap_NumberOfReportableSegments | 3 us-gaap_NumberOfReportableSegments
Minimum |  |
Number of reportable segments |  | 2 us-gaap_NumberOfReportableSegments / us-gaap_RangeAxis = us-gaap_MinimumMember
Length of fiscal year |  | 364 days
Maximum |  |
Number of reportable segments |  | 3 us-gaap_NumberOfReportableSegments / us-gaap_RangeAxis = us-gaap_MaximumMember
Length of fiscal year |  | 371 days

X
- Definition Represents the length of fiscal year of the company in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | acm_LengthOfFiscalYear
Namespace Prefix: | acm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NumberOfReportableSegments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |