XML 54 R39.htm IDEA: XBRL DOCUMENT
v3.10.0.1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - GAS IN STORAGE (Details) $ in Thousands | Jun. 30, 2018 USD ($) Bcf | Sep. 30, 2017 USD ($) Bcf
--- | --- | ---
Inventory [Line Items] |  |
Gas in Storage, value | $ | $ 136,284 | $ 202,063
Gas in Storage, Bcf | Bcf | 48.5 | 75.7
Energy Services |  |
Inventory [Line Items] |  |
Gas in Storage, value | $ | $ 86,889 | $ 122,884
Gas in Storage, Bcf | Bcf | 34.7 | 53.9
Natural Gas Distribution |  |
Inventory [Line Items] |  |
Gas in Storage, value | $ | $ 49,395 | $ 79,179
Gas in Storage, Bcf | Bcf | 13.8 | 21.8

X
- Definition Natural Gas in Storage Nonmonetary Number of Billion Cubic Feet of Gas in Storage as of the balance sheet date. + References No definition available. + Details
Name: | njr_EnergyRelatedInventoryNaturalGasinStorageBCF
Namespace Prefix: | njr_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of natural gas in storage, which is a mixture of gases (liquefied or otherwise), used for fuel and manufacturing purposes, which is ready for sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.6(a)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_EnergyRelatedInventoryNaturalGasInStorage
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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_InventoryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=njr_EnergyServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=njr_NaturalGasDistributionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |