DERIVATIVE INSTRUMENTS - OFFSETTING OF ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Home Services and Other
Derivative liabilities:
Amounts Presented in Balance Sheets	$ 10,796
Offsetting Derivative Instruments	0
Financial Collateral Received/Pledged	0
Net Amounts	10,796
Home Services and Other | Interest rate contracts
Derivative liabilities:
Amounts Presented in Balance Sheets	10,796
Offsetting Derivative Instruments	0
Financial Collateral Received/Pledged	0
Net Amounts	10,796
Energy Services
Derivative assets:
Amounts Presented in Balance Sheets	35,648	$ 32,080
Offsetting Derivative Instruments	(17,711)	(22,553)
Financial Collateral Received/Pledged	(200)	(200)
Net Amounts	17,737	9,327
Derivative liabilities:
Amounts Presented in Balance Sheets	54,519	75,629
Offsetting Derivative Instruments	(17,711)	(22,553)
Financial Collateral Received/Pledged	0	(15,516)
Net Amounts	36,808	37,560
Energy Services | Physical commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	8,111	8,557
Offsetting Derivative Instruments	(3,097)	(2,906)
Financial Collateral Received/Pledged	(200)	(200)
Net Amounts	4,814	5,451
Derivative liabilities:
Amounts Presented in Balance Sheets	39,690	40,181
Offsetting Derivative Instruments	(3,097)	(2,906)
Financial Collateral Received/Pledged	0	0
Net Amounts	36,593	37,275
Energy Services | Financial commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	27,499	23,522
Offsetting Derivative Instruments	(14,576)	(19,646)
Financial Collateral Received/Pledged	0	0
Net Amounts	12,923	3,876
Derivative liabilities:
Amounts Presented in Balance Sheets	14,576	35,162
Offsetting Derivative Instruments	(14,576)	(19,646)
Financial Collateral Received/Pledged	0	(15,516)
Net Amounts	0	0
Energy Services | Foreign currency contracts
Derivative assets:
Amounts Presented in Balance Sheets	38	1
Offsetting Derivative Instruments	(38)	(1)
Financial Collateral Received/Pledged	0	0
Net Amounts	0	0
Derivative liabilities:
Amounts Presented in Balance Sheets	253	286
Offsetting Derivative Instruments	(38)	(1)
Financial Collateral Received/Pledged	0	0
Net Amounts	215	285
Natural Gas Distribution
Derivative assets:
Amounts Presented in Balance Sheets	66	449
Offsetting Derivative Instruments	(39)	(391)
Financial Collateral Received/Pledged	0	0
Net Amounts	27	58
Derivative liabilities:
Amounts Presented in Balance Sheets	5,379	815
Offsetting Derivative Instruments	(39)	(391)
Financial Collateral Received/Pledged	(190)	(188)
Net Amounts	5,150	236
Natural Gas Distribution | Physical commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	66	67
Offsetting Derivative Instruments	(39)	(9)
Financial Collateral Received/Pledged	0	0
Net Amounts	27	58
Derivative liabilities:
Amounts Presented in Balance Sheets	133	245
Offsetting Derivative Instruments	(39)	(9)
Financial Collateral Received/Pledged	0	0
Net Amounts	94	236
Natural Gas Distribution | Financial commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets		382
Offsetting Derivative Instruments		(382)
Financial Collateral Received/Pledged		0
Net Amounts		0
Derivative liabilities:
Amounts Presented in Balance Sheets	190	570
Offsetting Derivative Instruments	0	(382)
Financial Collateral Received/Pledged	(190)	(188)
Net Amounts	0	$ 0
Natural Gas Distribution | Interest rate contracts
Derivative liabilities:
Amounts Presented in Balance Sheets	5,056
Offsetting Derivative Instruments	0
Financial Collateral Received/Pledged	0
Net Amounts	$ 5,056