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LONG-TERM DEBT - Schedule of Interest Expense Incurred (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Mar. 31, 2025 | Mar. 31, 2024
Debt Instrument [Line Items] |  |  |  |
Cash Interest, Capitalized Interest | $ (219) | $ (308) | $ (366) | $ (504)
Cash Interest | 22,889 | 25,091 | 46,747 | 49,334
Amort. Debt (Premium)/Discount | 22 | 30 | 45 | 61
Amort. Debt Issuance Costs & Other Fees | 1,019 | 1,028 | 2,025 | 2,053
Total Interest Expense | $ 23,930 | $ 26,149 | $ 48,817 | $ 51,448
Senior notes due 2028 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Effective Interest Rate | 6.00% | 6.00% | 6.00% | 6.00%
Cash Interest, Including Amounts Capitalized | $ 14,020 | $ 14,012 | $ 28,032 | $ 28,024
Amort. Debt (Premium)/Discount | (12) | (12) | (24) | (24)
Amort. Debt Issuance Costs & Other Fees | 505 | 505 | 1,010 | 1,010
Total Interest Expense | $ 14,513 | $ 14,505 | $ 29,018 | $ 29,010
Term Loan B due 2029 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Effective Interest Rate | 6.80% | 8.20% | 7.00% | 8.20%
Cash Interest, Including Amounts Capitalized | $ 7,328 | $ 9,027 | $ 15,383 | $ 18,244
Amort. Debt (Premium)/Discount | 34 | 42 | 69 | 85
Amort. Debt Issuance Costs & Other Fees | 312 | 331 | 625 | 661
Total Interest Expense | 7,674 | 9,400 | 16,077 | 18,990
Revolver due 2028 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Cash Interest, Including Amounts Capitalized | 1,669 | 2,231 | 3,546 | 3,139
Amort. Debt (Premium)/Discount | 0 | 0 | 0 | 0
Amort. Debt Issuance Costs & Other Fees | 187 | 187 | 373 | 373
Total Interest Expense | 1,856 | 2,418 | 3,919 | 3,512
Non US lines of credit |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Cash Interest, Including Amounts Capitalized | 72 | 14 | 74 | 14
Amort. Debt (Premium)/Discount | 0 | 0 | 0 | 0
Amort. Debt Issuance Costs & Other Fees | 15 | 4 | 17 | 8
Total Interest Expense | 87 | 18 | 91 | 22
Other long term debt |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Cash Interest, Including Amounts Capitalized | 19 | 115 | 78 | 417
Amort. Debt (Premium)/Discount | 0 | 0 | 0 | 0
Amort. Debt Issuance Costs & Other Fees | 0 | 1 | 0 | 1
Total Interest Expense | $ 19 | $ 116 | $ 78 | $ 418

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