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DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Sep. 30, 2019
--- | --- | ---
Natural Gas Distribution |  |
Derivative [Line Items] |  |
Broker margin - Current assets | $ 13,525 | $ 1,982
Energy Services |  |
Derivative [Line Items] |  |
Broker margin - Current assets | $ 55,919 | $ 71,741

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