XML 50 R35.htm IDEA: XBRL DOCUMENT
v2.4.1.9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - GAS IN STORAGE (Details) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2015 Bcf | Sep. 30, 2014 Bcf
--- | --- | ---
Inventory [Line Items] |  |
Gas in Storage | $ 71,402us-gaap_EnergyRelatedInventoryNaturalGasInStorage | $ 277,516us-gaap_EnergyRelatedInventoryNaturalGasInStorage
Gas in Storage (Bcf) | 23.5njr_GasStoredUndergroundBCF | 77.8njr_GasStoredUndergroundBCF
NJRES [Member] |  |
Inventory [Line Items] |  |
Gas in Storage | 65,030us-gaap_EnergyRelatedInventoryNaturalGasInStorage / dei_LegalEntityAxis = njr_NjresMember | 191,250us-gaap_EnergyRelatedInventoryNaturalGasInStorage / dei_LegalEntityAxis = njr_NjresMember
Gas in Storage (Bcf) | 22.0njr_GasStoredUndergroundBCF / dei_LegalEntityAxis = njr_NjresMember | 56.5njr_GasStoredUndergroundBCF / dei_LegalEntityAxis = njr_NjresMember
NJNG [Member] |  |
Inventory [Line Items] |  |
Gas in Storage | $ 6,372us-gaap_EnergyRelatedInventoryNaturalGasInStorage / dei_LegalEntityAxis = njr_NjngMember | $ 86,266us-gaap_EnergyRelatedInventoryNaturalGasInStorage / dei_LegalEntityAxis = njr_NjngMember
Gas in Storage (Bcf) | 1.5njr_GasStoredUndergroundBCF / dei_LegalEntityAxis = njr_NjngMember | 21.3njr_GasStoredUndergroundBCF / dei_LegalEntityAxis = njr_NjngMember

X
- Definition Gas Stored Underground (BCF) + References No definition available. + Details
Name: | njr_GasStoredUndergroundBCF
Namespace Prefix: | njr_
Data Type: | num:volumeItemType
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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 6 -Subparagraph a -Article 5 + Details
Name: | us-gaap_EnergyRelatedInventoryNaturalGasInStorage
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_InventoryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=njr_NjngMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=njr_NjresMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |