REGULATORY ASSETS & REGULATORY LIABILITIES - LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
South Jersey Gas Company
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 222,411	$ 245,360
South Jersey Gas Company | Excess Plant Removal Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	12,125	12,666
South Jersey Gas Company | Excess Deferred Taxes
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	206,902	232,694
South Jersey Gas Company | Deferred Gas Costs - Net
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	0	0
South Jersey Gas Company | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	3,384	0
SJI (parent company only)
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	398,951	420,577
SJI (parent company only) | Excess Plant Removal Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	46,113	50,619
SJI (parent company only) | Excess Deferred Taxes
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	317,905	346,582
SJI (parent company only) | Deferred Gas Costs - Net
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	28,842	22,291
SJI (parent company only) | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	6,091	1,085
ETG Utility Operations
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	176,540	175,217
ETG Utility Operations | Excess Plant Removal Costs
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	33,988	37,953
ETG Utility Operations | Excess Deferred Taxes
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	111,003	113,888
ETG Utility Operations | Deferred Gas Costs - Net
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	28,842	22,291
ETG Utility Operations | Other Regulatory Liabilities
Regulatory Liabilities [Line Items]
Total Regulatory Liabilities	$ 2,707	$ 1,085