SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - NATURAL GAS IN STORAGE (Details) $ in Thousands	Sep. 30, 2025 USD ($) Bcf	Sep. 30, 2024 USD ($) Bcf
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 215,836	$ 199,125
Natural Gas in Storage, Bcf | Bcf	44,300,000	43,900,000
NJNG
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 184,099	$ 177,655
Natural Gas in Storage, Bcf | Bcf	30,800,000	30,800,000
ES
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 30,686	$ 21,378
Natural Gas in Storage, Bcf | Bcf	13,200,000	13,100,000
S&T
Inventory [Line Items]
Natural Gas in Storage, value | $	$ 1,051	$ 92
Natural Gas in Storage, Bcf | Bcf	300,000	0