RESTRUCTURING CHARGES - Summary of the restructuring and other related charges (Details) $ in Thousands	12 Months Ended
	Sep. 30, 2020 USD ($)
Restructuring Cost and Reserve [Line Items]
Charges	$ 15,789
Personnel Related Costs
Restructuring Cost and Reserve [Line Items]
Charges	7,740
Facilities, Exit Costs and Other
Restructuring Cost and Reserve [Line Items]
Charges	3,357
Non-cash facility and other
Restructuring Cost and Reserve [Line Items]
Charges	4,692
Cost of Sales
Restructuring Cost and Reserve [Line Items]
Charges	4,159
Selling, General and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Charges	$ 11,630