LONG-TERM DEBT - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 22, 2020	Feb. 19, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Outstanding Balance	$ 1,149,903			$ 1,114,131
Less: current portion, outstanding balance	(9,235)			(10,525)
Long-term debt, outstanding balance	1,140,668			1,103,606
Original Issuer Premium	375			867
Less: current portion, original issuer premium, current	0			0
Long-term debt, original issuer premium, noncurrent	375			867
Capitalized Fees & Expenses	(17,678)			(10,724)
Balance Sheet	1,132,600			1,104,274
Less: current portion, balance sheet	(9,235)			(10,525)
Long-term debt, balance sheet	1,123,365			1,093,749
Senior notes due 2028
Debt Instrument [Line Items]
Outstanding Balance	1,000,000	$ 150,000		0
Original Issuer Premium	375			0
Capitalized Fees & Expenses	(14,877)			0
Balance Sheet	$ 985,498			$ 0
Coupon Interest Rate	5.75%	5.75%	5.75%	0.00%
Senior notes due 2022
Debt Instrument [Line Items]
Outstanding Balance	$ 0			$ 1,000,000
Original Issuer Premium	0			867
Capitalized Fees & Expenses	0			(9,175)
Balance Sheet	$ 0			$ 991,692
Coupon Interest Rate	5.25%		5.25%	5.25%
Revolver due 2025
Debt Instrument [Line Items]
Outstanding Balance	$ 104,181			$ 50,000
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(2,544)			(1,243)
Balance Sheet	101,637			48,757
Capital lease - real estate
Debt Instrument [Line Items]
Outstanding Balance	11,564			4,388
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(36)			(55)
Balance Sheet	$ 11,528			$ 4,333
Coupon Interest Rate	5.00%			5.00%
Non US lines of credit
Debt Instrument [Line Items]
Outstanding Balance	$ 0			$ 17,576
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(33)			(45)
Balance Sheet	(33)			17,531
Non US term loans
Debt Instrument [Line Items]
Outstanding Balance	30,736			36,977
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(172)			(188)
Balance Sheet	30,564			36,789
Other long term debt
Debt Instrument [Line Items]
Outstanding Balance	3,422			5,190
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(16)			(18)
Balance Sheet	$ 3,406			$ 5,172

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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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount, after accumulated amortization, of debt premium.

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Amount of debt premium to be amortized within one year or the normal operating cycle, if longer.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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