DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Natural Gas Distribution
Derivative [Line Items]
Broker margin - Current assets	$ 4,140	$ 1,982
Energy Services
Derivative [Line Items]
Broker margin - Current assets	$ 38,972	$ 71,741

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