DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Sep. 30, 2025
NJNG \| Assets, Current
Derivative [Line Items]
Broker margin - current assets	$ 5,582	$ 5,480
ES \| Assets, Current
Derivative [Line Items]
Broker margin - current assets	3,229	3,440
ES \| Liabilities, Current
Derivative [Line Items]
Broker margin - current liabilities	$ 1,111	$ 3,949

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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 25
-Paragraph 6A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480682/815-20-25-6A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480237/815-40-50-5

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+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 940
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481833/940-20-45-3

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