COMMITMENTS AND CONTINGENT LIABILITIES - SCHEDULE OF FUTURE COMMITTED EXPENSES (Details) $ in Thousands	6 Months Ended
Mar. 31, 2021 USD ($)
Long-term Purchase Commitment [Line Items]
Current charges recoverable through BGSS	$ 156,000
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	366,419
2022	242,784
2023	181,615
2024	192,097
2025	175,491
Thereafter	1,474,660
Energy Services
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	178,142
2022	63,472
2023	28,401
2024	21,991
2025	18,987
Thereafter	34,351
Energy Services \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	98,845
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	18,712
2022	14,248
2023	6,712
2024	3,318
2025	2,742
Thereafter	277
Energy Services \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	60,585
2022	49,224
2023	21,689
2024	18,673
2025	16,245
Thereafter	34,074
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	188,277
2022	179,312
2023	153,214
2024	170,106
2025	156,504
Thereafter	1,440,309
Natural Gas Distribution \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	32,320
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	37,285
2022	28,593
2023	17,090
2024	11,506
2025	2,207
Thereafter	2,495
Natural Gas Distribution \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2021	118,672
2022	150,719
2023	136,124
2024	158,600
2025	154,297
Thereafter	$ 1,437,814
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 second 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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