v3.25.1
Accumulated Other Comprehensive Loss, Net (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2025
Mar. 31, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance $ 1,777.4 $ 1,482.8 $ 1,709.1 $ 1,379.1
Other comprehensive loss, net of tax 18.6 (5.4) (6.6) 22.2
Ending balance 1,882.0 1,542.6 1,882.0 1,542.6
Foreign Currency Translation Adjustment        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance     (31.3)  
Other comprehensive loss, net of tax     (6.3)  
Ending balance (37.6)   (37.6)  
Pension Benefits Adjustment        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance     (1.2)  
Other comprehensive loss, net of tax     0.0  
Ending balance (1.2)   (1.2)  
Cash Flow Hedge        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance     7.3  
Other comprehensive loss, net of tax     (0.3)  
Ending balance 7.0   7.0  
Accumulated Other Comprehensive Loss, net        
AOCI Attributable to Parent, Net of Tax [Roll Forward]        
Beginning balance (50.4) (24.2) (25.2) (51.8)
Other comprehensive loss, net of tax 18.6 (5.4) (6.6) 22.2
Ending balance $ (31.8) $ (29.6) $ (31.8) $ (29.6)