LONG-TERM DEBT - Summary of Long-Term Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Feb. 20, 2020	Feb. 19, 2020	Sep. 30, 2019
Debt Instrument [Line Items]
Outstanding Balance	$ 1,242,500			$ 1,114,131
Less: current portion, outstanding balance	(9,470)			(10,525)
Long-term debt, outstanding balance	1,233,030			1,103,606
Original Issuer Premium	104			867
Less: current portion, original issuer premium, current	0			0
Long-term debt, original issuer premium, noncurrent	104			867
Capitalized Fees & Expenses	(16,908)			(10,724)
Balance Sheet	1,225,696			1,104,274
Less: current portion, balance sheet	(9,470)			(10,525)
Long-term debt, balance sheet	1,216,226			1,093,749
Senior notes due 2028
Debt Instrument [Line Items]
Outstanding Balance	850,000			0
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(12,854)			0
Balance Sheet	$ 837,146			$ 0
Coupon Interest Rate	5.75%		5.75%	0.00%
Senior notes due 2022
Debt Instrument [Line Items]
Outstanding Balance	$ 150,000	$ 150,000		$ 1,000,000
Original Issuer Premium	104			867
Capitalized Fees & Expenses	(1,098)			(9,175)
Balance Sheet	$ 149,006			$ 991,692
Coupon Interest Rate	5.25%		5.25%	5.25%
Revolver due 2025
Debt Instrument [Line Items]
Outstanding Balance	$ 183,548			$ 50,000
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(2,678)			(1,243)
Balance Sheet	180,870			48,757
Capital lease - real estate
Debt Instrument [Line Items]
Outstanding Balance	12,406			4,388
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(42)			(55)
Balance Sheet	$ 12,364			$ 4,333
Coupon Interest Rate	5.00%			5.00%
Non US lines of credit
Debt Instrument [Line Items]
Outstanding Balance	$ 9,532			$ 17,576
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(97)			(45)
Balance Sheet	9,435			17,531
Non US term loans
Debt Instrument [Line Items]
Outstanding Balance	33,462			36,977
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(122)			(188)
Balance Sheet	33,340			36,789
Other long term debt
Debt Instrument [Line Items]
Outstanding Balance	3,552			5,190
Original Issuer Premium	0			0
Capitalized Fees & Expenses	(17)			(18)
Balance Sheet	$ 3,535			$ 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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