XML 55 R34.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Basis of Presentation (Details) | 3 Months Ended
--- | ---
Dec. 31, 2012 item
Minimum |
Possible number of weeks in Company's fiscal year | 52
Maximum |
Possible number of weeks in Company's fiscal year | 53

X
- Definition Represents the possible number of weeks in the entity's fiscal year. + References No definition available. + Details
Name: | acm_PossibleNumberOfWeeksInFiscalYear
Namespace Prefix: | acm_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration