LINES OF CREDIT (Details) (USD $)	6 Months Ended
	Jun. 30, 2014		Jun. 30, 2013
Line of Credit Facility [Line Items]
Total facility	$ 610,000,000
Usage	223,900,000
Available liquidity	386,100,000
Letters of credit outstanding	17,200,000
Weighted average borrowing cost	1.16%		0.98%
Average borrowings outstanding during the period	320,200,000		275,300,000
Maximum amounts outstanding during the period	390,700,000		369,500,000
Financial covenant, ratio of indebtedness to consolidated total capitalization	0.65 to 1
Minimum [Member]
Line of Credit Facility [Line Items]
Financial covenant, ratio of indebtedness to consolidated total capitalization minimum	0.65
SJG Commercial Paper Program [Member]
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 [Member]
Line of Credit Facility [Line Items]
Total facility	210,000,000
Usage	10,000,000
Available liquidity	200,000,000
South Jersey Gas Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Total facility	200,000,000
Usage	10,000,000
Available liquidity	190,000,000
Expiration date	May 2018
South Jersey Gas Company [Member] | Uncommitted Bank Lines [Member]
Line of Credit Facility [Line Items]
Total facility	10,000,000
Usage	0
Available liquidity	10,000,000
Expiration date	Various
South Jersey Industries Inc [Member]
Line of Credit Facility [Line Items]
Total facility	400,000,000
Usage	213,900,000
Available liquidity	186,100,000
South Jersey Industries Inc [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Total facility	400,000,000	[1]
Usage	213,900,000	[1]
Available liquidity	$ 186,100,000	[1]
Expiration date	February 2018 (A)	[1]

[1] Includes letters of credit outstanding in the amount of $17.2 million.