XML 54 R61.htm IDEA: XBRL DOCUMENT
v3.20.1

DERIVATIVE INSTRUMENTS - CREDIT RISK EXPOSURE (Details) $ in Thousands | 6 Months Ended
--- | ---
Mar. 31, 2020 USD ($)
Credit Risk Exposure [Line Items] |
Gross Credit Exposure | $ 198,732
Investment grade |
Credit Risk Exposure [Line Items] |
Gross Credit Exposure | 125,043
Noninvestment grade |
Credit Risk Exposure [Line Items] |
Gross Credit Exposure | 12,310
Internally rated investment grade |
Credit Risk Exposure [Line Items] |
Gross Credit Exposure | 28,499
Internally rated noninvestment grade |
Credit Risk Exposure [Line Items] |
Gross Credit Exposure | $ 32,880

X
- Definition Maximum amount of loss due to credit risk that, based on the gross fair value of the financial instrument, the entity would incur if parties to the financial instruments that make up the concentration failed completely to perform according to the terms of the contracts and the collateral or other security, if any, for the amount due proved to be of no value to the entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611 + Details
Name: | us-gaap_ConcentrationRiskCreditRiskFinancialInstrumentMaximumExposure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_CreditDerivativesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_ExternalCreditRatingInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=us-gaap_ExternalCreditRatingNonInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=njr_InternallyRatedInvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InternalCreditAssessmentAxis=njr_InternallyRatedNoninvestmentGradeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |