LINES OF CREDIT AND SHORT-TERM BORROWINGS - Schedule of Lines of Credit (Weighted Average Interest Rates, Average Borrowings, and Maximum Amounts Outstanding) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Line of Credit Facility [Line Items]
Maximum amounts outstanding	$ 331,300	$ 177,100	$ 375,300	$ 452,900
South Jersey Gas Company
Line of Credit Facility [Line Items]
Maximum amounts outstanding	108,000	24,700	$ 108,000	$ 47,500
Line of Credit
Line of Credit Facility [Line Items]
Weighted average interest rate on borrowings (as a percent)			2.71%	0.18%
Average borrowings outstanding, not including LOC	157,834	57,100	$ 202,673	$ 211,800
Line of Credit | South Jersey Gas Company
Line of Credit Facility [Line Items]
Weighted average interest rate on borrowings (as a percent)			1.42%	0.18%
Average borrowings outstanding, not including LOC	$ 6,160	$ 4,400	$ 30,852	$ 12,800