XML 114 R84.htm IDEA: XBRL DOCUMENT v3.21.2
PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) - USD ($)
$ in Millions
12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
Property, Plant and Equipment [Line Items]      
Depreciation expense $ 51.9 $ 59.3 $ 76.4
HPC      
Property, Plant and Equipment [Line Items]      
Depreciation expense     $ 13.5