XML 72 R38.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Basis of Presentation (Details) | 3 Months Ended
--- | ---
Dec. 31, 2012
Minimum |
Length of fiscal year | 364 days
Maximum |
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