LEASES - ADDITIONAL INFORMATION (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Jul. 31, 2021
Lessee, Lease, Description [Line Items]
ROU asset obtained in exchange for operating lease liability	$ 6.4	$ 14.1
ROU asset obtained in exchange for finance lease liability	$ 0.0	$ 0.0
Weighted average remaining lease term, operating lease	28 years 4 months 24 days	28 years 7 months 6 days
Operating lease, discount rate	4.00%	3.80%
Weighted average remaining lease term, finance lease	2 years 4 months 24 days	3 years
Finance lease, discount rate	3.40%	3.40%
Solar Property | Minimum
Lessee, Lease, Description [Line Items]
Term of contract	20 years
Renewal term	5 years
Solar Property | Maximum
Lessee, Lease, Description [Line Items]
Term of contract	50 years
Renewal term	20 years
Office Building
Lessee, Lease, Description [Line Items]
Term of contract			16 years
Office Building | Minimum
Lessee, Lease, Description [Line Items]
Term of contract	2 years
Office Building | Maximum
Lessee, Lease, Description [Line Items]
Term of contract	11 years
Meter License | Minimum
Lessee, Lease, Description [Line Items]
Term of contract	7 years
Meter License | Maximum
Lessee, Lease, Description [Line Items]
Term of contract	10 years
Equipment
Lessee, Lease, Description [Line Items]
Term of contract	10 years
Storage and Capacity
Lessee, Lease, Description [Line Items]
Term of contract	50 years