FAIR VALUE MEASUREMENT OF FINANCIAL INSTRUMENTS - Supplemental Fair Value Information about Long-Term Fixed-Rate Debt (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net, carrying value	$ 545,292		$ 545,144
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities	28,523	$ 25,800	28,232	$ 23,745
Purchases	291	$ 2,055
Carrying value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net, carrying value	545,300		545,100
Fair value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, net, fair value	$ 471,600		$ 435,500