XML 74 R54.htm IDEA: XBRL DOCUMENT
v3.8.0.1

COMMON STOCK EQUITY - NARRATIVE (Details) - USD ($) shares in Thousands, $ in Millions | 3 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016
Equity [Abstract] |  |
Equity raised through the DRP | $ 3.8 | $ 4.6
Number of treasury shares issued from raising of equity through the DRP | 90 | 139
Equity raised through the DRP waiver discount feature | $ 22.7 |
Shares issued through the DRP waiver discount feature (in shares) | 554 |

X
- Definition Proceeds From Issuance Of Common Stock, Dividend Reinvestment Plan Waiver Discount Feature + References No definition available. + Details
Name: | njr_ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlanWaiverDiscountFeature
Namespace Prefix: | njr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares issued during the period from a DRP waiver discount feature. + References No definition available. + Details
Name: | njr_StockIssuedDuringPeriodSharesDividendReinvestmentPlanWaiverDiscountFeature
Namespace Prefix: | njr_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_EquityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cash inflow from capital contributions to an entity associated with a dividend reinvestment plan. + References No definition available. + Details
Name: | us-gaap_ProceedsFromIssuanceOfCommonStockDividendReinvestmentPlan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares issued during the period from a dividend reinvestment plan (DRIP). A dividend reinvestment plan allows the shareholders to reinvest dividends paid to them by the entity on new issues of stock by the entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesDividendReinvestmentPlan
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration