FAIR VALUE - ADDITIONAL INFORMATION (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Sep. 30, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance leases	$ 36,000	$ 31,400
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance leases	28,300	20,900
Fair market value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	2,218,977	2,106,536
Solar Asset Financing
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	284,200	278,400
Solar Asset Financing | Fair market value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 282,100	$ 268,100