DERIVATIVE INSTRUMENTS - OFFSETTING OF ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Sep. 30, 2019
Home Services and Other
Derivative liabilities:
Amounts Presented in Balance Sheets	$ 12,492
Offsetting Derivative Instruments	0
Financial Collateral Received/Pledged	0
Net Amounts	12,492
Home Services and Other | Interest rate contracts
Derivative liabilities:
Amounts Presented in Balance Sheets	12,492
Offsetting Derivative Instruments	0
Financial Collateral Received/Pledged	0
Net Amounts	12,492
Energy Services
Derivative assets:
Amounts Presented in Balance Sheets	43,951	$ 32,080
Offsetting Derivative Instruments	(17,560)	(22,553)
Financial Collateral Received/Pledged	(200)	(200)
Net Amounts	26,191	9,327
Derivative liabilities:
Amounts Presented in Balance Sheets	44,331	75,629
Offsetting Derivative Instruments	(17,560)	(22,553)
Financial Collateral Received/Pledged	(3,701)	(15,516)
Net Amounts	23,070	37,560
Energy Services | Physical commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	11,078	8,557
Offsetting Derivative Instruments	(4,493)	(2,906)
Financial Collateral Received/Pledged	(200)	(200)
Net Amounts	6,385	5,451
Derivative liabilities:
Amounts Presented in Balance Sheets	26,807	40,181
Offsetting Derivative Instruments	(4,493)	(2,906)
Financial Collateral Received/Pledged	0	0
Net Amounts	22,314	37,275
Energy Services | Financial commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	32,873	23,522
Offsetting Derivative Instruments	(13,067)	(19,646)
Financial Collateral Received/Pledged	0	0
Net Amounts	19,806	3,876
Derivative liabilities:
Amounts Presented in Balance Sheets	17,032	35,162
Offsetting Derivative Instruments	(13,067)	(19,646)
Financial Collateral Received/Pledged	(3,701)	(15,516)
Net Amounts	264	0
Energy Services | Foreign currency contracts
Derivative assets:
Amounts Presented in Balance Sheets		1
Offsetting Derivative Instruments		(1)
Financial Collateral Received/Pledged		0
Net Amounts		0
Derivative liabilities:
Amounts Presented in Balance Sheets	492	286
Offsetting Derivative Instruments	0	(1)
Financial Collateral Received/Pledged	0	0
Net Amounts	492	285
Natural Gas Distribution
Derivative assets:
Amounts Presented in Balance Sheets	131	449
Offsetting Derivative Instruments	(102)	(391)
Financial Collateral Received/Pledged	0	0
Net Amounts	29	58
Derivative liabilities:
Amounts Presented in Balance Sheets	6,891	815
Offsetting Derivative Instruments	(102)	(391)
Financial Collateral Received/Pledged	(24)	(188)
Net Amounts	6,765	236
Natural Gas Distribution | Physical commodity contracts
Derivative assets:
Amounts Presented in Balance Sheets	131	67
Offsetting Derivative Instruments	(102)	(9)
Financial Collateral Received/Pledged	0	0
Net Amounts	29	58
Derivative liabilities:
Amounts Presented in Balance Sheets	175	245
Offsetting Derivative Instruments	(102)	(9)
Financial Collateral Received/Pledged	0	0
Net Amounts	73	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	24	570
Offsetting Derivative Instruments	0	(382)
Financial Collateral Received/Pledged	(24)	(188)
Net Amounts	0	$ 0
Natural Gas Distribution | Interest rate contracts
Derivative liabilities:
Amounts Presented in Balance Sheets	6,692
Offsetting Derivative Instruments	0
Financial Collateral Received/Pledged	0
Net Amounts	$ 6,692