v3.25.1
Accumulated Other Comprehensive Loss (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($)
$ in Millions
 6 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Sep. 30, 2024
Dec. 31, 2023
Sep. 30, 2023
AOCI Attributable to Parent, Net of Tax [Roll Forward]            
Beginning balance $ (154.8)          
OCI before reclassifications (22.1) $ 10.7        
Reclassifications to earnings (0.3) (1.0)        
Ending balance (177.2)          
Stockholders' Equity Attributable to Parent 1,513.9 1,551.3 $ 1,501.0 $ 1,584.1 $ 1,545.8 $ 1,540.5
Foreign Currency Translation Adjustments            
AOCI Attributable to Parent, Net of Tax [Roll Forward]            
OCI before reclassifications (25.3) 11.0        
Reclassifications to earnings 0.0 0.0        
Stockholders' Equity Attributable to Parent (93.6) (75.9)   (68.3)   (86.9)
Pension and Post-retirement Activity            
AOCI Attributable to Parent, Net of Tax [Roll Forward]            
OCI before reclassifications (0.2) (1.2)        
Reclassifications to earnings 0.9 0.6        
Stockholders' Equity Attributable to Parent (84.1) (86.6)   (84.8)   (86.0)
Hedging Activity            
AOCI Attributable to Parent, Net of Tax [Roll Forward]            
OCI before reclassifications 3.4 0.9        
Reclassifications to earnings (1.2) (1.6)        
Stockholders' Equity Attributable to Parent 0.5 2.2   (1.7)   2.9
Accumulated other comprehensive loss            
AOCI Attributable to Parent, Net of Tax [Roll Forward]            
Stockholders' Equity Attributable to Parent $ (177.2) $ (160.3) $ (197.7) $ (154.8) $ (146.5) $ (170.0)