XML 29 R47.htm IDEA: XBRL DOCUMENT v3.2.0.727

DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014
Derivative [Line Items]
Broker margin - Current assets	$ 23,873	$ 27,339
NJNG [Member]
Derivative [Line Items]
Broker margin - Current assets	17,297	1,057
NJRES [Member]
Derivative [Line Items]
Broker margin - Current assets	$ 6,576	$ 26,282

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

X

- Definition

Amount of other receivables due from broker-dealers or clearing organizations.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherReceivablesFromBrokerDealersAndClearingOrganizations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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: