v3.25.1
Intangible Assets, net (Details) - USD ($)
$ in Millions
 6 Months Ended
Mar. 31, 2024
Mar. 31, 2025
Sep. 30, 2024
Finite-Lived Intangible Assets      
Finite-lived intangible assets, gross   $ 328.2 $ 328.2
Finite-lived intangible assets, accumulated amortization   (194.8) (186.4)
Finite-lived intangible assets, net   133.4 141.8
Accelerated amortization $ 17.4    
Customer relationships      
Finite-Lived Intangible Assets      
Finite-lived intangible assets, gross   160.7 160.7
Finite-lived intangible assets, accumulated amortization   (99.0) (94.6)
Finite-lived intangible assets, net   61.7 66.1
Trademarks and brands      
Finite-Lived Intangible Assets      
Finite-lived intangible assets, gross   164.4 164.4
Finite-lived intangible assets, accumulated amortization   (92.7) (88.7)
Finite-lived intangible assets, net   71.7 75.7
Other intangible assets      
Finite-Lived Intangible Assets      
Finite-lived intangible assets, gross   3.1 3.1
Finite-lived intangible assets, accumulated amortization   (3.1) (3.1)
Finite-lived intangible assets, net   $ 0.0 $ 0.0