RELATED PARTY TRANSACTIONS - DEMAND FEES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Sep. 30, 2022
Related Party Transaction [Line Items]
Demand fees payable	$ 856		$ 856		$ 851
Related Party
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	1,870	$ 1,838	5,467	$ 5,567
Demand fees payable	856		856		851
Related Party | NJNG to Steckman RIdge Affiliate
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	1,703	1,651	4,973	5,015
Demand fees payable	775		775		775
Related Party | NJRES to Steckman Ridge Affiliate
Related Party Transaction [Line Items]
Demand fees expense recognized pertaining to related party agreement	167	$ 187	494	$ 552
Demand fees payable	$ 81		$ 81		$ 76