SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - NATURAL GAS IN STORAGE (Details) $ in Thousands	Dec. 31, 2021 USD ($) Bcf	Sep. 30, 2021 USD ($) Bcf
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 242,692	$ 193,606
Natural Gas in Storage, Bcf | Bcf	51.6	46.4
Natural Gas Distribution
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 110,673	$ 115,824
Natural Gas in Storage, Bcf | Bcf	22.7	27.6
Energy Services
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 132,019	$ 77,782
Natural Gas in Storage, Bcf | Bcf	28.9	18.8