Income Taxes - Unrecognized tax benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Sep. 30, 2024 |
Sep. 30, 2023 |
Sep. 30, 2022 |
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| Income Tax Disclosure [Abstract] | |||
| Unrecognized Tax Benefits | $ 12.8 | $ 11.7 | $ 12.5 |
| Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions | 1.5 | 0.8 | 0.1 |
| Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions | 0.7 | 0.4 | 0.0 |
| Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities | (5.2) | (0.1) | (0.9) |
| Unrecognized Tax Benefits | 9.8 | 12.8 | 11.7 |
| Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 9.8 | ||
| Decrease in Unrecognized Tax Benefits is Reasonably Possible | 0.3 | ||
| Unrecognized Tax Expense (Benefits), Income Tax Penalties and Interest Expense | 0.4 | 0.5 | $ 0.1 |
| Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued | $ 1.5 | $ 1.1 | |
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- Definition Amount of decrease reasonably possible in the next twelve months for the unrecognized tax benefit. Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
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- References No definition available.
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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