SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - SOFTWARE COSTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Capitalized software costs	$ 7,625		$ 7,625		$ 6,120
Software amortization	125	$ 113	387	$ 339
Operation and maintenance
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Software costs	3,163	2,835	10,801	8,186
Depreciation and amortization
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Software costs	1,320	$ 637	3,148	$ 1,239
Utility plant, at cost
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Software costs	50,911		50,911		40,437
Construction work in progress | Regulated
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Software costs	41,533		41,533		14,381
Nonutility plant and equipment, at cost
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Software costs	344		344		344
Accumulated depreciation and amortization, utility plant
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Accumulated depreciation and amortization	(6,501)		(6,501)		(3,361)
Accumulated depreciation and amortization, nonutility plant and equipment
Capitalized Costs of Unproved Properties Excluded from Amortization [Line Items]
Accumulated depreciation and amortization	$ (33)		$ (33)		$ (25)