RELATED PARTY TRANSACTIONS - DEMAND FEES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Related Party Transaction [Line Items]
Demand fees payable	$ 859		$ 859		$ 859
Related Party
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	1,799	$ 1,770	3,678	$ 3,597
Demand fees payable	859		859		859
Related Party | NJNG to Steckman RIdge Affiliate
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	1,585	1,615	3,240	3,270
Demand fees payable	778		778		775
Related Party | NJRES to Steckman Ridge Affiliate
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	214	$ 155	438	$ 327
Demand fees payable	$ 81		$ 81		$ 84