RESTRUCTURING CHARGES - Summary of the restructuring and other related charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Charges	$ 21,418	$ 13,669
Personnel Related Costs
Restructuring Cost and Reserve [Line Items]
Charges	3,190	5,620
Facilities, Exit Costs and Other
Restructuring Cost and Reserve [Line Items]
Charges	11,573	3,357
Non-cash facility and other
Restructuring Cost and Reserve [Line Items]
Charges	6,655	4,692
Cost of Sales
Restructuring Cost and Reserve [Line Items]
Charges	7,923	4,159
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Charges	$ 13,495	$ 9,510