REGULATORY ASSETS AND REGULATORY LIABILITIES - Regulatory Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
South Jersey Gas Company
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 429,882	$ 482,745
South Jersey Gas Company | Environmental Remediation Costs: Expended - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	150,400	151,630
South Jersey Gas Company | Liability for Future Expenditures
Regulatory Assets [Line Items]
Total Regulatory Assets	91,470	97,964
South Jersey Gas Company | Deferred ARO Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	49,311	47,784
South Jersey Gas Company | Deferred Pension and Other Postretirement Benefit Costs - Unrecognized Prior Service Cost
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
South Jersey Gas Company | Deferred Pension and Other Postretirement Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	47,504	47,504
South Jersey Gas Company | Deferred Gas Costs - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	369	38,234
South Jersey Gas Company | CIP Receivable
Regulatory Assets [Line Items]
Total Regulatory Assets	14,522	17,776
South Jersey Gas Company | SBC Receivable (excluding RAC)
Regulatory Assets [Line Items]
Total Regulatory Assets	7,637	7,519
South Jersey Gas Company | Deferred Interest Rate Contracts
Regulatory Assets [Line Items]
Total Regulatory Assets	6,017	8,002
South Jersey Gas Company | EET/EEP
Regulatory Assets [Line Items]
Total Regulatory Assets	16,786	20,632
South Jersey Gas Company | AFUDC - Equity Related Deferrals
Regulatory Assets [Line Items]
Total Regulatory Assets	12,345	12,199
South Jersey Gas Company | WNC
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
South Jersey Gas Company | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	9,401	7,687
South Jersey Gas Company | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	24,120	25,814
SJI
Regulatory Assets [Line Items]
Total Regulatory Assets	624,229	672,416
SJI | Environmental Remediation Costs: Expended - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	172,009	165,602
SJI | Liability for Future Expenditures
Regulatory Assets [Line Items]
Total Regulatory Assets	166,199	175,794
SJI | Deferred ARO Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	84,830	81,656
SJI | Deferred Pension and Other Postretirement Benefit Costs - Unrecognized Prior Service Cost
Regulatory Assets [Line Items]
Total Regulatory Assets	30,062	30,881
SJI | Deferred Pension and Other Postretirement Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	48,317	48,317
SJI | Deferred Gas Costs - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	369	38,234
SJI | CIP Receivable
Regulatory Assets [Line Items]
Total Regulatory Assets	18,737	20,731
SJI | SBC Receivable (excluding RAC)
Regulatory Assets [Line Items]
Total Regulatory Assets	7,637	7,519
SJI | Deferred Interest Rate Contracts
Regulatory Assets [Line Items]
Total Regulatory Assets	6,017	8,002
SJI | EET/EEP
Regulatory Assets [Line Items]
Total Regulatory Assets	20,766	25,831
SJI | AFUDC - Equity Related Deferrals
Regulatory Assets [Line Items]
Total Regulatory Assets	12,345	12,199
SJI | WNC
Regulatory Assets [Line Items]
Total Regulatory Assets	1,160	4,269
SJI | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	22,005	17,912
SJI | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	33,776	35,469
ETG Utility Operations
Regulatory Assets [Line Items]
Total Regulatory Assets	194,347	189,671
ETG Utility Operations | Environmental Remediation Costs: Expended - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	21,609	13,972
ETG Utility Operations | Liability for Future Expenditures
Regulatory Assets [Line Items]
Total Regulatory Assets	74,729	77,830
ETG Utility Operations | Deferred ARO Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	35,519	33,872
ETG Utility Operations | Deferred Pension and Other Postretirement Benefit Costs - Unrecognized Prior Service Cost
Regulatory Assets [Line Items]
Total Regulatory Assets	30,062	30,881
ETG Utility Operations | Deferred Pension and Other Postretirement Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	813	813
ETG Utility Operations | Deferred Gas Costs - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
ETG Utility Operations | CIP Receivable
Regulatory Assets [Line Items]
Total Regulatory Assets	4,215	2,955
ETG Utility Operations | SBC Receivable (excluding RAC)
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
ETG Utility Operations | Deferred Interest Rate Contracts
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
ETG Utility Operations | EET/EEP
Regulatory Assets [Line Items]
Total Regulatory Assets	3,980	5,199
ETG Utility Operations | AFUDC - Equity Related Deferrals
Regulatory Assets [Line Items]
Total Regulatory Assets	0	0
ETG Utility Operations | WNC
Regulatory Assets [Line Items]
Total Regulatory Assets	1,160	4,269
ETG Utility Operations | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	12,604	10,225
ETG Utility Operations | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 9,656	$ 9,655