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Organization (Narrative) (Details) $ in Millions | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2024 USD ($) business_segments | Jun. 30, 2023 USD ($) | Jun. 30, 2024 USD ($) | Jun. 30, 2023 USD ($) | Sep. 30, 2023 USD ($) | Sep. 30, 2022 USD ($)
Segment Reporting Information [Line Items] |  |  |  |  |  |
Restructuring | $ 4.1 | $ 2.2 | $ 4.1 | $ 2.2 | $ 6.6 | $ 3.3
Restructuring Reserve, Accrual Adjustment |  |  | 12.7 | 0.9 |  |
Gain (Loss) on Sale of Properties |  |  |  | 4.0 |  |
Pension costs (benefits) other then service | $ 1.0 | $ 0.9 | $ 3.0 | $ 2.8 |  |
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent | 21.00% | 21.00% | 21.00% | 21.00% |  |
Number of Reportable Segments | business_segments | 2 |  |  |  |  |
Other Sundry Liabilities, Noncurrent | $ 3.9 |  | $ 3.9 |  |  |
Asset Impairment Charges |  |  | 1.4 | $ 0.0 |  |
Proceeds from Other Equity, Gross Amount | 4.8 |  | 4.8 |  |  |
Intercompany Loan related to NMTC | 12.2 |  | 12.2 |  |  |
Investment Fund Contribution for NMTC | 16.5 |  | 16.5 |  |  |
Sub-CDE loan from NMTC | $ 16.2 |  | $ 16.2 |  |  |

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