FAIR VALUE - ADDITIONAL INFORMATION (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance leases	$ 37,400	$ 31,600
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance leases	35,200	26,700
Fair market value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	2,423,763	2,525,804
Solar Asset Financing
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	289,700	283,000
Solar Asset Financing | Fair market value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 292,400	$ 290,400