FAIR VALUE - ADDITIONAL INFORMATION (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance leases	$ 38,200	$ 31,400
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance leases	29,800	20,900
Fair market value | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	2,334,582	2,106,536
Solar Asset Financing
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	296,300	278,400
Solar Asset Financing | Fair market value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 297,000	$ 268,100