REGULATORY ASSETS AND REGULATORY LIABILITIES - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
South Jersey Gas Company
Regulatory Assets [Line Items]
Regulatory assets	$ 429,882		$ 482,745
South Jersey Gas Company | Environmental Remediation
Regulatory Assets [Line Items]
Original recovery period of expenditures	7 years
South Jersey Gas Company | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Regulatory assets	$ 9,401		7,687
South Jersey Gas Company | Judicial Ruling | Pricing dispute, long-term gas supply contract
Regulatory Assets [Line Items]
Amount paid to third party supplier	17,100	$ 1,600	21,300
ETG Utility Operations | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Regulatory assets	$ 12,600		$ 10,200