GOODWILL AND INTANGIBLE ASSETS - Narrative (Details) - USD ($)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	May 28, 2021
Intangible Assets [Line Items]
Write-off from impairment of intangible assets	$ 0	$ 0	$ 24,200,000
Impairment, Intangible Asset, Indefinite-Lived (Excluding Goodwill), Statement of Income or Comprehensive Income [Extensible Enumeration]			Write-off from impairment of intangible assets
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]			Write-off from impairment of intangible assets
Goodwill	953,100,000	867,200,000	$ 627,200,000
Amortization of intangible assets	50,300,000	65,100,000	55,300,000
Rejuvenate
Intangible Assets [Line Items]
Goodwill				$ 147,000,000.0
Rejuvenate | Tradenames
Intangible Assets [Line Items]
Goodwill	119,100,000
Coevorden operations
Intangible Assets [Line Items]
Impairment loss recognized on definite-lived intangible assets		7,600,000
Coevorden operations | Tradenames
Intangible Assets [Line Items]
Impairment loss recognized on indefinite-lived intangible assets		16,600,000
HPC
Intangible Assets [Line Items]
Goodwill	$ 108,100,000	$ 0	$ 0