LONG-TERM DEBT	9 Months Ended
Sep. 30, 2011
Long-term Debt, Unclassified [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT: During the first nine months of 2010, SJG issued $60.0 million aggregate principal amount of its Medium Term Notes in private placements due 2026. In September 2011, SJG entered into an arrangement to issue Medium Term Notes under a private placement in an aggregate principal amount of $35.0 million. SJG expects to issue this debt in April 2012. In the third quarter 2011, SJG repaid $25.0 million of First Mortgage Bonds. As of September 30, 2011 the $150.0 million Medium Term Note program that was approved by the BPU in September 2009 expired. In September 2011, SJG filed a petition with the BPU to establish a new $200.0 million MTN program. The estimated fair values of SJI’s long-term debt, including current maturities, as of September 30, 2011 and December 31, 2010, were $530.9 million and $517.0 million, respectively. The carrying amounts of SJI’s long-term debt, including current maturities, as of September 30, 2011 and December 31, 2010, were $426.4 million and 451.4 million, respectively. We based the estimates on interest rates available to SJI at the end of each period for debt with similar terms and maturities. The carrying amounts of SJI’s other financial instruments approximate their fair values at September 30, 2011 and December 31, 2010.

LONG-TERM DEBT:

During the first nine months of 2010, SJG issued $60.0 million aggregate principal amount of its Medium Term Notes in private placements due 2026. In September 2011, SJG entered into an arrangement to issue Medium Term Notes under a private placement in an aggregate principal amount of $35.0 million. SJG expects to issue this debt in April 2012. In the third quarter 2011, SJG repaid $25.0 million of First Mortgage Bonds. As of September 30, 2011 the $150.0 million Medium Term Note program that was approved by the BPU in September 2009 expired. In September 2011, SJG filed a petition with the BPU to establish a new $200.0 million MTN program.

The estimated fair values of SJI’s long-term debt, including current maturities, as of September 30, 2011 and December 31, 2010, were $530.9 million and $517.0 million, respectively. The carrying amounts of SJI’s long-term debt, including current maturities, as of September 30, 2011 and December 31, 2010, were $426.4 million and 451.4 million, respectively. We based the estimates on interest rates available to SJI at the end of each period for debt with similar terms and maturities. The carrying amounts of SJI’s other financial instruments approximate their fair values at September 30, 2011 and December 31, 2010.