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Supplemental Statement of Operations Information (Details) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2017 | Sep. 30, 2016 | Sep. 30, 2015
Schedule of Statement of Operations Supplemental Disclosures [Line Items] |  |  |
Restructuring Reserve | $ 3.3 | $ 0.0 |
Included in selling, general and administrative expenses: |  |  |
Research and development | 12.1 | 9.9 | $ 12.1
Advertising | 5.2 | 4.0 | 4.0
Interest expense, net: |  |  |
Interest rate swap contracts | 1.9 | 0.0 | 0.0
Deferred financing fees amortization | 1.8 | 1.9 | 2.0
Other interest expense | 0.6 | 0.5 | 0.2
Interest Expense | 24.2 | 24.0 | 27.8
Interest income | (2.0) | (0.4) | (0.3)
Interest expense, net | (22.2) | (23.6) | (27.5)
Other Cost and Expense, Operating | 10.4 | 7.2 | 7.9
Secured Debt [Member] |  |  |
Interest expense, net: |  |  |
Debt instrument interest expense | 19.1 | 20.5 | 17.5
Seven Point Three Seven Five Senior Subordinated Notes [Member] |  |  |
Interest expense, net: |  |  |
Debt instrument interest expense | 0.0 | 0.0 | 4.0
Eight Point Seven Five Senior Unsecured Notes [Member] |  |  |
Interest expense, net: |  |  |
Debt instrument interest expense | 0.0 | 0.0 | 2.4
ABL Agreement [Member] |  |  |
Interest expense, net: |  |  |
Debt instrument interest expense | 0.8 | 1.1 | $ 1.7
Statesboro [Member] |  |  |
Interest expense, net: |  |  |
Other Cost and Expense, Operating |  | $ 4.1 |
Mueller One Project [Member] |  |  |
Interest expense, net: |  |  |
Other Cost and Expense, Operating | $ 4.2 |  |

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