LINES OF CREDIT (Details)		6 Months Ended
		Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)
Line of Credit Facility [Line Items]
Total Facility		$ 610,000,000
Usage		379,100,000
Available Liquidity		230,900,000
Letters of credit outstanding		$ 13,100,000
Weighted average borrowing cost		0.96%	1.16%
Average borrowings outstanding during the period		$ 274,300,000	$ 320,200,000
Maximum amounts outstanding during the period		$ 368,100,000	$ 390,700,000
Financial covenant, ratio of indebtedness to consolidated total capitalization		0.65 to 1
Minimum
Line of Credit Facility [Line Items]
Financial covenant, ratio of indebtedness to consolidated total capitalization minimum		0.65
SJG Commercial Paper Program
Line of Credit Facility [Line Items]
Total Facility		$ 200,000,000
Fixed maturities of notes, at maximum number of days (in days)		270 days
South Jersey Gas Company
Line of Credit Facility [Line Items]
Total Facility		$ 210,000,000
Usage		127,600,000
Available Liquidity		82,400,000
South Jersey Gas Company | Revolving Credit Facility
Line of Credit Facility [Line Items]
Total Facility		200,000,000
Usage		127,600,000
Available Liquidity		72,400,000
South Jersey Gas Company | Uncommitted Bank Lines
Line of Credit Facility [Line Items]
Total Facility		10,000,000
Usage		0
Available Liquidity		10,000,000
South Jersey Industries Inc
Line of Credit Facility [Line Items]
Total Facility		400,000,000
Usage		251,500,000
Available Liquidity		148,500,000
South Jersey Industries Inc | Revolving Credit Facility
Line of Credit Facility [Line Items]
Total Facility	[1]	400,000,000
Usage	[1]	251,500,000
Available Liquidity	[1]	$ 148,500,000

[1] Includes letters of credit outstanding in the amount of $13.1 million.