LONG-TERM DEBT - Summary of Interest Expense Incurred (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Cash Interest, Capitalized Interest	$ (73)	$ (7)
Cash Interest	15,027	15,010
Amort. Debt Premium	(12)	0
Amort. Debt Issuance Costs & Other Fees	666	680
Total Interest Expense	$ 15,681	$ 15,690
Senior notes due 2028
Debt Instrument [Line Items]
Effective Interest Rate	5.90%	5.90%
Cash Interest, Including Amounts Capitalized	$ 14,375	$ 14,375
Amort. Debt Premium	(12)	0
Amort. Debt Issuance Costs & Other Fees	518	530
Total Interest Expense	14,881	14,905
Revolver due 2025
Debt Instrument [Line Items]
Cash Interest, Including Amounts Capitalized	261	129
Amort. Debt Premium	0	0
Amort. Debt Issuance Costs & Other Fees	122	123
Total Interest Expense	$ 383	$ 252
Finance lease - real estate
Debt Instrument [Line Items]
Effective Interest Rate	5.60%	4.80%
Cash Interest, Including Amounts Capitalized	$ 198	$ 232
Amort. Debt Premium	0	0
Amort. Debt Issuance Costs & Other Fees	4	6
Total Interest Expense	202	238
Non US lines of credit
Debt Instrument [Line Items]
Cash Interest, Including Amounts Capitalized	3	3
Amort. Debt Premium	0	0
Amort. Debt Issuance Costs & Other Fees	4	4
Total Interest Expense	7	7
Non US term loans
Debt Instrument [Line Items]
Cash Interest, Including Amounts Capitalized	166	171
Amort. Debt Premium	0	0
Amort. Debt Issuance Costs & Other Fees	17	17
Total Interest Expense	183	188
Other long term debt
Debt Instrument [Line Items]
Cash Interest, Including Amounts Capitalized	97	107
Amort. Debt Premium	0	0
Amort. Debt Issuance Costs & Other Fees	1	0
Total Interest Expense	$ 98	$ 107