LONG-TERM DEBT - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Sep. 30, 2025
Debt Instrument [Line Items]
Outstanding Balance	$ 1,364,159	$ 1,424,026
less: Current portion	(8,119)	(8,103)
Long-term debt	1,356,040	1,415,923
Original Issuer Premium/(Discount)	(262)	(340)
Capitalized Fees & Expenses	(9,668)	(11,196)
Balance Sheet	1,354,229	1,412,490
less: Current portion	(8,119)	(8,103)
Long-term debt	1,346,110	1,404,387
Senior notes due 2028
Debt Instrument [Line Items]
Outstanding Balance	974,775	974,775
Original Issuer Premium/(Discount)	109	121
Capitalized Fees & Expenses	(4,376)	(4,880)
Balance Sheet	$ 970,508	$ 970,016
Coupon Interest Rate	5.75%	5.75%
Term Loan B due 2029
Debt Instrument [Line Items]
Outstanding Balance	$ 389,000	$ 449,000
Original Issuer Premium/(Discount)	(371)	(461)
Capitalized Fees & Expenses	(3,356)	(4,169)
Balance Sheet	385,273	444,370
Revolver due 2028
Debt Instrument [Line Items]
Outstanding Balance	0	0
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	(1,927)	(2,113)
Balance Sheet	(1,927)	(2,113)
Non US lines of credit
Debt Instrument [Line Items]
Outstanding Balance	0	0
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	(9)	(34)
Balance Sheet	(9)	(34)
Other debt
Debt Instrument [Line Items]
Outstanding Balance	384	251
Original Issuer Premium/(Discount)	0	0
Capitalized Fees & Expenses	0	0
Balance Sheet	$ 384	$ 251