LONG-TERM DEBT - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Sep. 30, 2021	Jun. 22, 2020
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	$ 1,610,835	$ 1,060,506
less: Current portion, Outstanding Balance	(13,085)	(12,486)
Long-term debt, Outstanding Balance, Non-current	1,597,750	1,048,020
Original Issuer Premium/(Discount)	(909)	315
Capitalized Fees & Expenses	(22,144)	(15,138)
Long-term debt, Balance Sheet	1,587,782	1,045,683
less: Current portion, Balance Sheet	(13,085)	(12,486)
Long-term debt, Balance Sheet, Non-current	1,574,697	1,033,197
Senior notes due 2028
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	984,775	1,000,000
Original Issuer Premium/(Discount)	278	315
Capitalized Fees & Expenses	(11,562)	(13,293)
Long-term debt, Balance Sheet	$ 973,491	$ 987,022
Coupon Interest Rate	5.75%	5.75%	5.75%
Term Loan B due 2029
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	$ 498,000	$ 0
Original Issuer Premium/(Discount)	(1,187)	0
Capitalized Fees & Expenses	(9,174)	0
Long-term debt, Balance Sheet	487,639	0
Revolver due 2025
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	97,816	13,483
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	(1,350)	(1,718)
Long-term debt, Balance Sheet	96,466	11,765
Finance lease - real estate
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	13,426	14,594
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	0	(4)
Long-term debt, Balance Sheet	13,426	14,590
Non US lines of credit
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	0	3,012
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	(6)	(17)
Long-term debt, Balance Sheet	(6)	2,995
Non US term loans
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	14,193	25,684
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	(39)	(91)
Long-term debt, Balance Sheet	14,154	25,593
Other long term debt
Debt Instrument [Line Items]
Long-term debt, Outstanding Balance	2,625	3,733
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	(13)	(15)
Long-term debt, Balance Sheet	$ 2,612	$ 3,718

Amount of long term capitalized fees and expenses.

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The current portion of long term debt gross value.

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The carrying amount of long-term debt, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities).

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt discount (premium).

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Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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