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NATURE OF THE BUSINESS (Details) |  | 9 Months Ended
--- | --- | ---
Jun. 01, 2018 MW | Jun. 30, 2018 subsidiary customer
Steckman Ridge |  |
Nature of Business [Line Items] |  |
Equity method investment, ownership percentage |  | 50.00%
PennEast |  |
Nature of Business [Line Items] |  |
Equity method investment, ownership percentage |  | 20.00%
Natural Gas Distribution |  |
Nature of Business [Line Items] |  |
Total retail customers | customer |  | 537,700
NJR Retail Holdings Corporation |  |
Nature of Business [Line Items] |  |
Number of principal subsidiaries | subsidiary |  | 2
Clean Energy Ventures |  |
Nature of Business [Line Items] |  |
Wind farm total capacity | MW | 9.7 |

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