COMMITMENTS AND CONTINGENT LIABILITIES - LEGAL PROCEEDINGS (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Loss Contingencies [Line Items]
Manufactured gas plant remediation	$ 161,650	$ 169,390
Recovery from third party of environmental remediation cost, period	7 years
Regulatory assets	$ 609,192	$ 584,830
Expended, net of recoveries
Loss Contingencies [Line Items]
Regulatory assets	77,500
Minimum
Loss Contingencies [Line Items]
Product liability contingency, loss exposure in excess of accrual, best estimate	130,900
Maximum
Loss Contingencies [Line Items]
Product liability contingency, loss exposure in excess of accrual, best estimate	$ 194,600