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Shareholders' Equity - Class of Treasury Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands | 12 Months Ended
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Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Equity, Class of Treasury Stock [Line Items] |  |  |
Treasury Stock Acquired, Average Cost Per Share | $ 266.04 | $ 177.08 | $ 142.62
Stock Repurchased and Retired During Period, Value | $ 500,037 | $ 500,056 | $ 350,049
October 26, 2010 Program [Member] |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |
Stock Repurchased and Retired During Period, Shares | 1,879 | 2,824 | 2,454

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