v3.26.1
FAIR VALUE MEASUREMENT OF FINANCIAL INSTRUMENTS - Schedule of Supplemental Fair Value Information about Long-Term Fixed-Rate Debt (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Sep. 30, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net $ 1,855,257 $ 2,057,084
Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 1,733,696 1,927,001
Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 69,237 74,254
2027 Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net 348,446 347,675
2027 Notes | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2027 Notes | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 349,793 352,261
2027 Notes | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2029 Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net 347,158 346,602
2029 Notes | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2029 Notes | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 350,315 348,688
2029 Notes | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2031 Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net 546,787 546,336
2031 Notes | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2031 Notes | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 494,197 486,343
2031 Notes | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2034 Notes    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net 543,629 543,197
2034 Notes | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2034 Notes | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 539,391 538,417
2034 Notes | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2027 Term Loan    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net   199,020
2027 Term Loan | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value   0
2027 Term Loan | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value   201,292
2027 Term Loan | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value   0
2023 Oman Facility    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net 32,970 35,465
2023 Oman Facility | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2023 Oman Facility | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2023 Oman Facility | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 32,970 35,465
2024 Oman Facility    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, net 36,267 38,789
2024 Oman Facility | Level 1    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2024 Oman Facility | Level 2    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value 0 0
2024 Oman Facility | Level 3    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Long-term debt, excluding current maturities, fair value $ 36,267 $ 38,789