PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Mar. 31, 2018	Mar. 31, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		$ 2,177,000	$ 1,382,000
Interest Cost		5,108,000	2,955,000
Expected Return on Plan Assets		(7,633,000)	(3,524,000)
Amortizations:
Prior Service Cost		71,000	33,000
Actuarial Loss		4,132,000	2,613,000
Net Periodic Benefit Cost		3,855,000	3,459,000
Capitalized Benefit Cost		(483,000)	(1,271,000)
Deferred Benefit Cost		(751,000)	(161,000)
Total Net Periodic Benefit Expense		2,621,000	2,027,000
Contributions	$ 10,000,000	0
Estimated future contributions		0
Pension Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		2,500,000	2,500,000
Contributions	$ 8,000,000
Estimated future contributions		0
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		81,000	247,000
Interest Cost		217,000	601,000
Expected Return on Plan Assets		(305,000)	(853,000)
Amortizations:
Prior Service Cost		(31,000)	(86,000)
Actuarial Loss		111,000	312,000
Net Periodic Benefit Cost		73,000	221,000
Capitalized Benefit Cost		(5,000)	(55,000)
Total Net Periodic Benefit Expense		68,000	166,000
Defined benefit plan regulatory obligation to contribute to the plan during the period		3,600,000
Other Postretirement Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		100,000	$ 100,000
Supplemental executive retirement plan
Amortizations:
Estimated future contributions		$ 2,400,000