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Major Clients (Details) - Revenue - Customer Concentration Risk | 12 Months Ended
--- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Percentage of total revenue |  |  |
Period for which criteria of threshold percentage for disclosure not met in past | 5 years |  |
Agencies of U.S. Federal Government |  |  |
Percentage of total revenue |  |  |
Concentration risk (as percent) | 7.00% | 7.00% | 5.00%

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