REGULATORY ASSETS & REGULATORY LIABILITIES - ASSETS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
South Jersey Gas Company
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 482,745	$ 495,084
South Jersey Gas Company | Environmental Remediation Costs: Expended - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	151,630	157,340
South Jersey Gas Company | Environmental Restoration Costs: Liability for Future Expenditures
Regulatory Assets [Line Items]
Total Regulatory Assets	97,964	101,243
South Jersey Gas Company | Environmental Remediation Costs: Insurance Recovery Receivables
Regulatory Assets [Line Items]
Insurance Recovery Receivables		0
South Jersey Gas Company | Deferred ARO Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	47,784	42,365
South Jersey Gas Company | Deferred Pension 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	77,426
South Jersey Gas Company | Deferred Gas Costs - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	38,234	19,178
South Jersey Gas Company | CIP Receivable
Regulatory Assets [Line Items]
Total Regulatory Assets	17,776	21,013
South Jersey Gas Company | SBC Receivable (excluding RAC)
Regulatory Assets [Line Items]
Total Regulatory Assets	7,519	3,453
South Jersey Gas Company | Deferred Interest Rate Contracts
Regulatory Assets [Line Items]
Total Regulatory Assets	8,002	9,938
South Jersey Gas Company | EET/EEP
Regulatory Assets [Line Items]
Total Regulatory Assets	20,632	18,725
South Jersey Gas Company | AFUDC - Equity Related Deferrals
Regulatory Assets [Line Items]
Total Regulatory Assets	12,199	11,822
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	7,687	4,737
South Jersey Gas Company | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	25,814	27,844
SJI (parent company only)
Regulatory Assets [Line Items]
Total Regulatory Assets	672,416	673,992
SJI (parent company only) | Environmental Remediation Costs: Expended - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	165,602	162,536
SJI (parent company only) | Environmental Restoration Costs: Liability for Future Expenditures
Regulatory Assets [Line Items]
Total Regulatory Assets	175,794	193,080
SJI (parent company only) | Environmental Remediation Costs: Insurance Recovery Receivables
Regulatory Assets [Line Items]
Insurance Recovery Receivables		(6,807)
SJI (parent company only) | Deferred ARO Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	81,656	67,818
SJI (parent company only) | Deferred Pension Costs - Unrecognized Prior Service Cost
Regulatory Assets [Line Items]
Total Regulatory Assets	30,881	33,898
SJI (parent company only) | Deferred Pension and Other Postretirement Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	48,317	85,892
SJI (parent company only) | Deferred Gas Costs - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	38,234	19,178
SJI (parent company only) | CIP Receivable
Regulatory Assets [Line Items]
Total Regulatory Assets	20,731	21,013
SJI (parent company only) | SBC Receivable (excluding RAC)
Regulatory Assets [Line Items]
Total Regulatory Assets	7,519	3,453
SJI (parent company only) | Deferred Interest Rate Contracts
Regulatory Assets [Line Items]
Total Regulatory Assets	8,002	9,938
SJI (parent company only) | EET/EEP
Regulatory Assets [Line Items]
Total Regulatory Assets	25,831	21,787
SJI (parent company only) | AFUDC - Equity Related Deferrals
Regulatory Assets [Line Items]
Total Regulatory Assets	12,199	11,822
SJI (parent company only) | WNC
Regulatory Assets [Line Items]
Total Regulatory Assets	4,269	7,444
SJI (parent company only) | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	17,912	10,555
SJI (parent company only) | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	35,469	32,385
ETG Utility Operations
Regulatory Assets [Line Items]
Total Regulatory Assets	189,671	178,908
ETG Utility Operations | Environmental Remediation Costs: Expended - Net
Regulatory Assets [Line Items]
Total Regulatory Assets	13,972	5,196
ETG Utility Operations | Environmental Restoration Costs: Liability for Future Expenditures
Regulatory Assets [Line Items]
Total Regulatory Assets	77,830	91,837
ETG Utility Operations | Environmental Remediation Costs: Insurance Recovery Receivables
Regulatory Assets [Line Items]
Total Regulatory Assets	20,400
Insurance Recovery Receivables		(6,807)
ETG Utility Operations | Deferred ARO Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	33,872	25,453
ETG Utility Operations | Deferred Pension Costs - Unrecognized Prior Service Cost
Regulatory Assets [Line Items]
Total Regulatory Assets	30,881	33,898
ETG Utility Operations | Deferred Pension and Other Postretirement Benefit Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	813	8,466
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	2,955	0
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	5,199	3,062
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	4,269	7,444
ETG Utility Operations | Deferred COVID-19 Costs
Regulatory Assets [Line Items]
Total Regulatory Assets	10,225	5,818
ETG Utility Operations | Other Regulatory Assets
Regulatory Assets [Line Items]
Total Regulatory Assets	$ 9,655	$ 4,541