DERIVATIVE INSTRUMENTS - BALANCE SHEET RELATED DISCLOSURES (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021
Fair Value
Derivative assets, current	$ 39,783	$ 35,251
Derivative liabilities, current	30,049	87,145
Derivative assets, noncurrent	1,978	3,403
Derivative liabilities, noncurrent	15,261	13,497
Not Designated as Hedging Instrument
Fair Value
Derivative assets	41,761	38,654
Derivative liabilities	45,310	100,642
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Physical commodity contracts
Fair Value
Derivative assets, current	234	36
Derivative liabilities, current	4	16
Natural Gas Distribution \| Not Designated as Hedging Instrument \| Financial commodity contracts
Fair Value
Derivative assets, current	5,032	2,046
Derivative liabilities, current	240	13
Energy Services \| Not Designated as Hedging Instrument \| Physical commodity contracts
Fair Value
Derivative assets, current	2,285	2,818
Derivative liabilities, current	18,592	24,592
Derivative assets, noncurrent	135	333
Derivative liabilities, noncurrent	15,261	13,237
Energy Services \| Not Designated as Hedging Instrument \| Financial commodity contracts
Fair Value
Derivative assets, current	32,164	30,226
Derivative liabilities, current	11,209	62,521
Derivative assets, noncurrent	1,843	3,068
Derivative liabilities, noncurrent	0	260
Energy Services \| Not Designated as Hedging Instrument \| Foreign currency contracts
Fair Value
Derivative assets, current	68	125
Derivative liabilities, current	4	3
Derivative assets, noncurrent	0	2
Derivative liabilities, noncurrent	$ 0	$ 0

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