PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		$ 639,000	$ 1,112,000	$ 2,816,000	$ 2,494,000
Interest Cost		716,000	2,931,000	5,824,000	5,886,000
Expected Return on Plan Assets		(19,000)	(3,529,000)	(7,652,000)	(7,053,000)
Amortizations:
Prior Service Cost		(13,000)	33,000	58,000	66,000
Actuarial Loss		1,632,000	2,528,000	5,764,000	5,141,000
Net Periodic Benefit Cost		2,955,000	3,075,000	6,810,000	6,534,000
Capitalized Benefit Cost		(554,000)	(1,129,000)	(1,037,000)	(2,400,000)
Deferred Benefit Cost		(374,000)	(139,000)	(1,125,000)	(300,000)
Total Net Periodic Benefit Expense		2,027,000	1,807,000	4,648,000	3,834,000
Contributions	$ 10,000,000			0
Estimated future contributions		0		0
Pension Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		1,900,000	2,300,000	4,300,000	4,800,000
Contributions	$ 8,000,000
Estimated future contributions		0		0
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service Cost		360,000	208,000	441,000	455,000
Interest Cost		859,000	609,000	1,076,000	1,209,000
Expected Return on Plan Assets		(1,578,000)	(853,000)	(1,883,000)	(1,705,000)
Amortizations:
Prior Service Cost		(141,000)	(86,000)	(172,000)	(172,000)
Actuarial Loss		340,000	307,000	451,000	619,000
Net Periodic Benefit Cost		(160,000)	185,000	(87,000)	406,000
Capitalized Benefit Cost		0	(46,000)	(5,000)	(101,000)
Total Net Periodic Benefit Expense		(160,000)	139,000	(92,000)	305,000
Other Postretirement Benefits | South Jersey Gas Company
Amortizations:
Net Periodic Benefit Cost		100,000	$ 100,000	100,000	$ 200,000
Supplemental executive retirement plan
Amortizations:
Estimated future contributions		$ 2,400,000		$ 2,400,000