SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - PPE Utility (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Production Plant	$ 241	$ 1,334
Storage Plant	82,313	90,294
Transmission Plant	345,716	338,981
Distribution Plant	4,703,918	4,330,797
General Plant	430,940	428,737
Other Plant	1,955	1,955
Utility Plant In Service	5,565,083	5,192,098
Construction Work In Progress	117,722	73,563
Total Utility Plant	5,682,805	5,265,661
Accumulated Depreciation	(975,619)	(914,122)
Property, Plant and Equipment - Net	4,707,186	4,351,539
Nonutility Property and Equipment	240,503	147,764
Accumulated Depreciation	(35,367)	(35,069)
Net Nonutility Property and Equipment	205,136	112,695
Solar Assets
Property, Plant and Equipment [Line Items]
Nonutility Property and Equipment	61,478	40,380
Fuel Cell Assets
Property, Plant and Equipment [Line Items]
Nonutility Property and Equipment	80,550	80,546
Other Assets
Property, Plant and Equipment [Line Items]
Nonutility Property and Equipment	24,711	26,838
Construction Work In Progress
Property, Plant and Equipment [Line Items]
Nonutility Property and Equipment	73,764	0
South Jersey Gas Company
Property, Plant and Equipment [Line Items]
Production Plant	25	25
Storage Plant	62,140	61,971
Transmission Plant	322,051	311,272
Distribution Plant	2,923,016	2,705,893
General Plant	264,194	265,185
Other Plant	1,855	1,855
Utility Plant In Service	3,573,281	3,346,201
Construction Work In Progress	40,079	41,630
Total Utility Plant	3,613,360	3,387,831
Accumulated Depreciation	(656,829)	(606,925)
Property, Plant and Equipment - Net	$ 2,956,531	$ 2,780,906