PREFERRED STOCK	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
PREFERRED STOCK	PREFERRED STOCK: REDEEMABLE CUMULATIVE PREFERRED STOCK - SJI has 2,500,000 authorized shares of Preference Stock, no par value, which has not been issued.

The entire disclosure for terms, amounts, nature of changes, rights and privileges, dividends, and other matters related to preferred stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-URI http://asc.fasb.org/topic&trid=2208762

Name:	us-gaap_PreferredStockTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration