PENSION AND OTHER POSTRETIREMENT BENEFITS - NET PERIODIC BENEFIT COST (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated percent of employees who will be entitled to annuity payments	30.00%
Pension Benefits
Net periodic benefit cost [Abstract]
Service Cost	$ 5,887	$ 5,871	$ 5,583
Interest Cost	13,028	15,017	17,294
Expected Return on Plan Assets	(23,762)	(21,929)	(20,195)
Amortization:
Prior Service Credits	98	105	105
Actuarial Loss	12,932	10,845	9,550
Net Periodic Benefit Credits	8,183	9,909	12,337
Settlement, Curtailment and Special Termination Costs	44	781	955
Capitalized Benefit Costs	(1,551)	(1,969)	(2,008)
Affiliate SERP Allocations	0	0
Deferred Benefit Costs	(1,168)	(1,591)	(2,411)
Total Net Periodic Benefit Income	5,508	7,130	8,873
Other Postretirement Benefits
Net periodic benefit cost [Abstract]
Service Cost	814	681	533
Interest Cost	1,920	2,367	2,884
Expected Return on Plan Assets	(5,741)	(5,381)	(4,571)
Amortization:
Prior Service Credits	(624)	(624)	(561)
Actuarial Loss	1,118	853	1,163
Net Periodic Benefit Credits	(2,513)	(2,104)	(552)
Capitalized Benefit Costs	(225)	(209)	(201)
Affiliate SERP Allocations	0	(84)
Deferred Benefit Costs	1,164	935	357
Total Net Periodic Benefit Income	$ (1,574)	(1,378)	(396)
South Jersey Gas Company
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Estimated percent of employees who will be entitled to annuity payments	28.00%
South Jersey Gas Company | Pension Benefits
Net periodic benefit cost [Abstract]
Service Cost	$ 3,778	3,797	3,621
Interest Cost	8,481	9,695	11,067
Expected Return on Plan Assets	(13,403)	(11,903)	(11,028)
Amortization:
Prior Service Credits	88	95	95
Actuarial Loss	11,569	9,364	8,224
Net Periodic Benefit Credits	10,513	11,048	11,979
Capitalized Benefit Costs	(1,551)	(1,395)	(1,437)
Affiliate SERP Allocations	0	0
Deferred Benefit Costs	(1,168)	(1,591)	(2,411)
Total Net Periodic Benefit Income	3,066	4,124	4,590
South Jersey Gas Company | Supplemental Employee Retirement Plan
Amortization:
Affiliate SERP Allocations	(4,728)	(3,938)	(3,541)
South Jersey Gas Company | Other Postretirement Benefits
Net periodic benefit cost [Abstract]
Service Cost	480	396	343
Interest Cost	1,181	1,463	1,863
Expected Return on Plan Assets	(4,041)	(3,860)	(3,220)
Amortization:
Prior Service Credits	(502)	(502)	(474)
Actuarial Loss	884	672	1,042
Net Periodic Benefit Credits	(1,998)	(1,831)	(446)
Capitalized Benefit Costs	(225)	(166)	(155)
Affiliate SERP Allocations	0	(13)
Deferred Benefit Costs	1,164	935	357
Total Net Periodic Benefit Income	$ (1,059)	$ (1,062)	$ (244)