SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - NATURAL GAS IN STORAGE (Details) $ in Thousands	Mar. 31, 2022 USD ($) Bcf	Sep. 30, 2021 USD ($) Bcf
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 66,300	$ 193,606
Natural Gas in Storage, Bcf | Bcf	12,300,000	46,400,000
Natural Gas Distribution
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 31,066	$ 115,824
Natural Gas in Storage, Bcf | Bcf	4,900,000	27,600,000
Energy Services
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 35,234	$ 77,782
Natural Gas in Storage, Bcf | Bcf	7,400,000	18,800,000