DERIVATIVE INSTRUMENTS - Effect of Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Derivatives not designated as hedging instruments under GAAP
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gains (Losses) on energy-related commodity contracts	$ 11,300	$ (19,800)	$ (43,900)	$ (35,100)
Interest Rate Contracts | Non-Utility Revenue
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Losses reclassified from AOCL into income	(11)	(12)	(35)	(35)
Interest Rate Contracts | Non-Utility Revenue | SJG
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Losses reclassified from AOCL into income	(11)	(12)	(35)	(35)
Energy-related Commodity Contracts | Derivatives not designated as hedging instruments under GAAP
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gains (Losses) on energy-related commodity contracts	$ 11,319	$ (19,815)	$ (43,872)	$ (35,089)