DERIVATIVE INSTRUMENTS - Effect of Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Interest rate contracts \| Non-Utility Revenue
Interest Rate Derivatives [Abstract]
Losses reclassified from AOCL into income	$ (13)	$ (12)
South Jersey Gas Company \| Interest rate contracts \| Non-Utility Revenue
Interest Rate Derivatives [Abstract]
Losses reclassified from AOCL into income	(13)	(12)
Derivatives not designated as hedging instruments under GAAP
Interest Rate Derivatives [Abstract]
Losses on energy-related commodity contracts	(21,300)	(100)
Derivatives not designated as hedging instruments under GAAP \| Energy-related commodity contracts
Interest Rate Derivatives [Abstract]
Losses on energy-related commodity contracts	$ (21,268)	$ (44)

Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e637-108580

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959

Name:	us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration