v3.22.2.2
GOODWILL AND INTANGIBLE ASSETS, NET - Rollforward of Carrying Amount of Goodwill by Reportable Segment (Details) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Goodwill [Roll Forward]    
Goodwill, gross (beginning of period) $ 701.6 $ 640.5
Accumulated impairment losses (96.4) (96.4)
Goodwill, net (beginning of period) 605.2 544.1
Acquisitions and measurement-period adjustments 180.8 60.5
Foreign currency translation (9.6) 0.6
Reallocation   0.0
Impairment (522.4)  
Goodwill, gross (end of period) 872.8 701.6
Accumulated impairment losses (618.8) (96.4)
Goodwill, net (end of period) 254.0 605.2
U.S. Consumer    
Goodwill [Roll Forward]    
Goodwill, gross (beginning of period) 245.7 229.9
Accumulated impairment losses (1.8) (1.8)
Goodwill, net (beginning of period) 243.9 228.1
Acquisitions and measurement-period adjustments 0.0 0.0
Foreign currency translation 0.0 0.0
Reallocation 15.8 15.8
Impairment 0.0  
Goodwill, gross (end of period) 245.7 245.7
Accumulated impairment losses (1.8) (1.8)
Goodwill, net (end of period) 243.9 243.9
Hawthorne    
Goodwill [Roll Forward]    
Goodwill, gross (beginning of period) 444.8 400.1
Accumulated impairment losses (94.6) (94.6)
Goodwill, net (beginning of period) 350.2 305.5
Acquisitions and measurement-period adjustments 180.8 60.5
Foreign currency translation (8.6) 0.0
Reallocation (15.8) (15.8)
Impairment (522.4)  
Goodwill, gross (end of period) 617.0 444.8
Accumulated impairment losses (617.0) (94.6)
Goodwill, net (end of period) 0.0 350.2
Other    
Goodwill [Roll Forward]    
Goodwill, gross (beginning of period) 11.1 10.5
Accumulated impairment losses 0.0 0.0
Goodwill, net (beginning of period) 11.1 10.5
Acquisitions and measurement-period adjustments 0.0 0.0
Foreign currency translation (1.0) 0.6
Reallocation   0.0
Impairment 0.0  
Goodwill, gross (end of period) 10.1 11.1
Accumulated impairment losses 0.0 0.0
Goodwill, net (end of period) $ 10.1 $ 11.1