COMMITMENTS AND CONTINGENT LIABILITIES - SCHEDULE OF FUTURE COMMITTED EXPENSES (Details) $ in Thousands	3 Months Ended
Dec. 31, 2019 USD ($)
Long-term Purchase Commitment [Line Items]
Current charges recoverable through BGSS	$ 101,000
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	418,863
2021	244,090
2022	215,133
2023	175,432
2024	133,368
Thereafter	680,544
Energy Services
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	307,280
2021	103,059
2022	58,926
2023	30,654
2024	17,756
Thereafter	48,319
Energy Services \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	227,340
2021	25,248
2022	0
2023	0
2024	0
Thereafter	0
Energy Services \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	18,767
2021	15,205
2022	11,378
2023	6,805
2024	1,650
Thereafter	935
Energy Services \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	61,173
2021	62,606
2022	47,548
2023	23,849
2024	16,106
Thereafter	47,384
Natural Gas Distribution
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	111,583
2021	141,031
2022	156,207
2023	144,778
2024	115,612
Thereafter	632,225
Natural Gas Distribution \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	10,606
2021	30,615
2022	30,402
2023	30,862
2024	31,845
Thereafter	32,248
Natural Gas Distribution \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	29,014
2021	33,751
2022	25,406
2023	18,744
2024	12,176
Thereafter	10,209
Natural Gas Distribution \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2020	71,963
2021	76,665
2022	100,399
2023	95,172
2024	71,591
Thereafter	$ 589,768
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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Storage and Pipeline Capacity, Term of Contract

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Minimum amount of purchase arrangement maturing after the fifth fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

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Minimum amount of purchase arrangement maturing in the fourth fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

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Minimum amount of purchase arrangement maturing in the next fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

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Minimum amount of purchase arrangement maturing in the second fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

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Minimum amount of purchase arrangement maturing in the third fiscal year following the latest fiscal year. Includes, but not limited to, recorded and unrecorded purchase obligations, long-term purchase commitments, and short-term purchase commitments.

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