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Major Clients (Details) (Revenue, Percentage of total revenue) | 12 Months Ended
--- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2011
Percentage of total revenue |  |  |
Period for which criteria of threshold percentage for disclosure not met in past | 5 years |  |
Maximum |  |  |
Percentage of total revenue |  |  |
Percentage of revenue accounted for by no other single client (as a percent) | 10.00% |  |
Agencies of the U.S. federal government |  |  |
Percentage of total revenue |  |  |
Percentage of the Company's revenue (as a percent) | 18.00% | 18.00% | 22.00%
Agencies of the U.S. federal government | Management Support Services |  |  |
Percentage of total revenue |  |  |
Percentage of the Company's revenue (as a percent) | 4.00% | 4.00% | 3.00%

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