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Allowance for Doubtful Accounts - Schedule of Activity of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions | 12 Months Ended
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Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Balance, beginning of year | $ 51.9 | $ 59.9 | $ 47.8
Provision (recovery) for bad debts | 2.3 | (2.4) | 12.5
Allowance charge-offs | (0.3) | (6.2) | (0.5)
Other | 0.0 | 0.6 | 0.1
Balance, end of year | 53.9 | 51.9 | 59.9
Bad debt expense not included in allowance | $ 0.8 | $ 3.0 | $ 4.0

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- Definition SEC Schedule, 12-09, Valuation Allowances And Reserves, Credit Loss Expense (Reversal) Not Included In Allowance + References No definition available. + Details
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- Definition Amount of valuation and qualifying accounts and reserves. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org/1943274/2147480738/235-10-S50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column B)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 235 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09(Column E)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480678/235-10-S99-4 + Details
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