SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - NATURAL GAS IN STORAGE (Details) $ in Thousands, Bcf in Millions	Sep. 30, 2023 USD ($) Bcf	Sep. 30, 2022 USD ($) Bcf
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 199,501	$ 273,644
Natural Gas in Storage, Bcf | Bcf	43.7	39.8
NJNG
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 175,025	$ 191,175
Natural Gas in Storage, Bcf | Bcf	29.1	29.0
ES
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 24,476	$ 82,469
Natural Gas in Storage, Bcf | Bcf	14.6	10.8