LINES OF CREDIT (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Line of Credit Facility [Line Items]
Total facility	$ 610,000,000
Usage	341,500,000
Available liquidity	268,500,000
Letters of credit outstanding	17,200,000
Weighted average borrowing cost	1.06%		1.02%
Average borrowings outstanding during the period	332,200,000		317,300,000
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	47,700,000
Available liquidity	162,300,000
South Jersey Gas Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Total facility	200,000,000
Usage	47,700,000
Available liquidity	152,300,000
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	August 2014
South Jersey Industries Inc [Member]
Line of Credit Facility [Line Items]
Total facility	400,000,000
Usage	293,800,000
Available liquidity	106,200,000
South Jersey Industries Inc [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Total facility	400,000,000	[1]
Usage	293,800,000	[1]
Available liquidity	$ 106,200,000	[1]
Expiration date	February 2018 (A)	[1]

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