DERIVATIVE INSTRUMENTS - OFFSETTING OF ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Energy Services
Derivative assets:
Amounts Presented in Balance Sheets	$ 25,514	$ 36,572
Offsetting Derivative Instruments	(18,798)	(34,191)
Financial Collateral Received/Pledged	(200)	19,832
Net Amounts	6,516	22,213
Derivative liabilities:
Amounts Presented in Balance Sheets	62,945	100,613
Offsetting Derivative Instruments	(18,798)	(34,191)
Financial Collateral Received/Pledged	0	0
Net Amounts	44,147	66,422
Energy Services | Physical commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	1,984	3,151
Offsetting Derivative Instruments	(480)	(894)
Financial Collateral Received/Pledged	(200)	(700)
Net Amounts	1,304	1,557
Derivative liabilities:
Amounts Presented in Balance Sheets	41,226	37,829
Offsetting Derivative Instruments	(480)	(894)
Financial Collateral Received/Pledged	0	0
Net Amounts	40,746	36,935
Energy Services | Financial commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	23,492	33,294
Offsetting Derivative Instruments	(18,300)	(33,294)
Financial Collateral Received/Pledged	0	20,532
Net Amounts	5,192	20,532
Derivative liabilities:
Amounts Presented in Balance Sheets	21,701	62,781
Offsetting Derivative Instruments	(18,300)	(33,294)
Financial Collateral Received/Pledged	0	0
Net Amounts	3,401	29,487
Energy Services | Foreign currency contracts
Derivative assets:
Amounts Presented in Balance Sheets	38	127
Offsetting Derivative Instruments	(18)	(3)
Financial Collateral Received/Pledged	0	0
Net Amounts	20	124
Derivative liabilities:
Amounts Presented in Balance Sheets	18	3
Offsetting Derivative Instruments	(18)	(3)
Financial Collateral Received/Pledged	0	0
Net Amounts	0	0
Natural Gas Distribution
Derivative assets:
Amounts Presented in Balance Sheets	212	2,082
Offsetting Derivative Instruments	(119)	(21)
Financial Collateral Received/Pledged	0	0
Net Amounts	93	2,061
Derivative liabilities:
Amounts Presented in Balance Sheets	1,903	29
Offsetting Derivative Instruments	(119)	(21)
Financial Collateral Received/Pledged	0	0
Net Amounts	1,784	8
Natural Gas Distribution | Physical commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	101	36
Offsetting Derivative Instruments	(8)	(8)
Financial Collateral Received/Pledged	0	0
Net Amounts	93	28
Derivative liabilities:
Amounts Presented in Balance Sheets	16	16
Offsetting Derivative Instruments	(8)	(8)
Financial Collateral Received/Pledged	0	0
Net Amounts	8	8
Natural Gas Distribution | Financial commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	111	2,046
Offsetting Derivative Instruments	(111)	(13)
Financial Collateral Received/Pledged	0	0
Net Amounts	0	2,033
Derivative liabilities:
Amounts Presented in Balance Sheets	1,887	13
Offsetting Derivative Instruments	(111)	(13)
Financial Collateral Received/Pledged	0	0
Net Amounts	$ 1,776	$ 0