AFFILIATIONS, DISCONTINUED OPERATIONS AND RELATED-PARTY TRANSACTIONS - Related Party Transactions (Details) - South Jersey Gas Company - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating Revenues/Affiliates:
Total Operating Revenues/Affiliates	$ 2,854	$ 447	$ 11,155	$ 6,796
Operations Expense/Affiliates:
Total Operations Expense/Affiliates	8,882	7,584	17,208	15,046
SJRG
Operating Revenues/Affiliates:
Total Operating Revenues/Affiliates	2,833	426	11,113	6,755
Cost of sales/affiliates	36	2,603	116	3,970
SJI (parent company only)
Operations Expense/Affiliates:
Total Operations Expense/Affiliates	6,724	5,685	13,096	11,249
SJIU
Operations Expense/Affiliates:
Total Operations Expense/Affiliates	1,204	952	2,210	1,912
Millennium
Operations Expense/Affiliates:
Total Operations Expense/Affiliates	932	874	1,862	1,740
Other
Operating Revenues/Affiliates:
Total Operating Revenues/Affiliates	21	21	42	41
Operations Expense/Affiliates:
Total Operations Expense/Affiliates	$ 22	$ 73	$ 40	$ 145