DERIVATIVE INSTRUMENTS - BALANCE SHEET RELATED DISCLOSURES (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Fair Value
Derivative assets, current	$ 33,087	$ 23,310
Derivative liabilities, current	24,444	33,865
Derivative assets, noncurrent	1,547	3,349
Derivative liabilities, noncurrent	14,933	13,352
Not Designated as Hedging Instrument
Fair Value
Derivative assets	34,634	26,659
Derivative liabilities	39,377	47,217
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Physical commodity contracts
Fair Value
Derivative assets, current	1	78
Derivative liabilities, current	176	76
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Financial commodity contracts
Fair Value
Derivative assets, current	723	71
Derivative liabilities, current	574	282
Energy Services \| Not Designated as Hedging Instrument \| Physical commodity contracts
Fair Value
Derivative assets, current	6,416	6,454
Derivative liabilities, current	16,815	20,438
Derivative assets, noncurrent	1,159	1,264
Derivative liabilities, noncurrent	12,668	12,003
Energy Services \| Not Designated as Hedging Instrument \| Financial commodity contracts
Fair Value
Derivative assets, current	25,784	16,671
Derivative liabilities, current	6,866	12,965
Derivative assets, noncurrent	333	2,037
Derivative liabilities, noncurrent	2,265	1,346
Energy Services \| Not Designated as Hedging Instrument \| Foreign currency contracts
Fair Value
Derivative assets, current	163	36
Derivative liabilities, current	13	104
Derivative assets, noncurrent	55	48
Derivative liabilities, noncurrent	$ 0	$ 3

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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