SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - NATURAL GAS IN STORAGE (Details) $ in Thousands	Dec. 31, 2024 USD ($) Bcf	Sep. 30, 2024 USD ($) Bcf
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 192,046	$ 199,125
Natural Gas in Storage, Bcf | Bcf	38,100,000	43,900,000
NJNG
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 161,613	$ 177,655
Natural Gas in Storage, Bcf | Bcf	25,300,000	30,800,000
ES
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 30,311	$ 21,378
Natural Gas in Storage, Bcf | Bcf	12,700,000	13,100,000
S&T
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 122	$ 92
Natural Gas in Storage, Bcf | Bcf	100,000	0