COMMITMENTS AND CONTINGENCIES (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) employee	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) employee
Loss Contingencies [Line Items]
Number of employees | employee	1,155		1,130
Approximate amount accrued related to all claims	$ 4,300,000		$ 4,100,000
REV LNG
Loss Contingencies [Line Items]
Committed capital contribution, up to	25,000,000.0
Related party notes receivable	19,300,000		$ 19,300,000
REV LNG | Forecast
Loss Contingencies [Line Items]
Remaining notes receivable		$ 5,700,000
SJG
Loss Contingencies [Line Items]
Approximate amount accrued related to all claims	$ 1,200,000
SJG | Unionized Collective Bargaining Agreements
Loss Contingencies [Line Items]
Number of employees with labor union representation | employee	304		303
Parental Guarantee
Loss Contingencies [Line Items]
Parental guarantees	$ 11,400,000
Guarantee expiration period	1 year
ETG Utility Operations
Loss Contingencies [Line Items]
Minimum annual fee for long-term asset management agreement	$ 4,250,000
ETG Utility Operations | Unionized Collective Bargaining Agreements
Loss Contingencies [Line Items]
Number of employees with labor union representation | employee	164		167