DERIVATIVE INSTRUMENTS - BROKER MARGIN DEPOSITS (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Natural Gas Distribution
Derivative [Line Items]
Broker margin - Current assets	$ 2,116	$ 1,982
Energy Services
Derivative [Line Items]
Broker margin - Current assets	$ 21,830	$ 71,741

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.

No definition available.

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