RELATED PARTY TRANSACTIONS - DEMAND FEES (Details) - Related Party - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	$ 5,952	$ 7,147	$ 7,206
Demand fees payable	641	875
NJNG to Steckman RIdge Affiliate
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	5,184	6,319	6,549
Demand fees payable	540	775
ES to Steckman Ridge Affiliate
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	768	828	$ 657
Demand fees payable	$ 101	$ 100