COMMITMENTS AND CONTINGENT LIABILITIES - SCHEDULE OF FUTURE COMMITTED EXPENSES (Details) $ in Thousands	3 Months Ended
Dec. 31, 2020 USD ($)
Long-term Purchase Commitment [Line Items]
Current charges recoverable through BGSS	$ 133,700
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	365,654
2022	226,707
2023	156,275
2024	123,533
2025	105,923
Thereafter	593,289
Energy Services
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	222,095
2022	61,630
2023	32,213
2024	23,612
2025	17,896
Thereafter	36,108
Energy Services \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	134,236
2022	0
2023	0
2024	0
2025	0
Thereafter	0
Energy Services \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	18,481
2022	12,625
2023	6,836
2024	3,118
2025	2,256
Thereafter	552
Energy Services \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	69,378
2022	49,005
2023	25,377
2024	20,494
2025	15,640
Thereafter	35,556
Annual pipeline obligation to be paid over 10 year period	4,000
Natural Gas Distribution
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	143,559
2022	165,077
2023	124,062
2024	99,921
2025	88,027
Thereafter	557,181
Natural Gas Distribution \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	9,880
2022	0
2023	0
2024	0
2025	0
Thereafter	0
Natural Gas Distribution \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	36,128
2022	29,764
2023	17,204
2024	12,152
2025	4,532
Thereafter	3,043
Natural Gas Distribution \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	97,551
2022	135,313
2023	106,858
2024	87,769
2025	83,495
Thereafter	$ 554,138
Minimum \| Energy Services
Long-term Purchase Commitment [Line Items]
Storage and pipeline capacity, contract term	1 year
Maximum \| Energy Services
Long-term Purchase Commitment [Line Items]
Storage and pipeline capacity, contract term	10 years

Current Charges Recoverable Through Basic Gas Supply Service as shown for the reporting period

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Purchase Obligation, To Be Paid, After Year Four

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Recorded Unconditional Purchase Obligation, To Be Paid Annual By Counterparty Over 10 Year Period

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Storage and Pipeline Capacity, Term of Contract

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Amount of purchase arrangement to be paid in fourth fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of purchase arrangement to be paid in third fiscal year following current fiscal year. Includes, but is not limited to, recorded and unrecorded purchase obligations, long-term purchase commitment, and short-term purchase commitment. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of recorded unconditional purchase obligation to be paid in remainder of current fiscal year.

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