COMMITMENTS AND CONTINGENT LIABILITIES - SCHEDULE OF FUTURE COMMITTED EXPENSES (Details) $ in Thousands	9 Months Ended
Jun. 30, 2024 USD ($)
Long-term Purchase Commitment [Line Items]
Current charges recoverable through BGSS	$ 237,700
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	92,202
2025	325,994
2026	222,698
2027	172,253
2028	138,802
Thereafter	1,004,236
ES
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	34,561
2025	79,983
2026	51,556
2027	31,855
2028	19,961
Thereafter	37,230
ES \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	9,998
2025	17,151
2026	1,090
2027	0
2028	0
Thereafter	0
ES \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	4,135
2025	16,119
2026	11,716
2027	5,452
2028	3,500
Thereafter	6,780
ES \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	20,428
2025	46,713
2026	38,750
2027	26,403
2028	16,461
Thereafter	30,450
Annual pipeline obligation to be paid over 10 year period	4,000
NJNG
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	57,641
2025	246,011
2026	171,142
2027	140,398
2028	118,841
Thereafter	967,006
NJNG \| Natural gas purchases
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	7,517
2025	0
2026	0
2027	0
2028	0
Thereafter	0
NJNG \| Storage demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	11,284
2025	38,199
2026	22,632
2027	11,160
2028	4,877
Thereafter	0
NJNG \| Pipeline demand fees
Natural Gas Purchases and Future Demand Fees, Next Five Fiscal Years
2024	38,840
2025	207,812
2026	148,510
2027	129,238
2028	113,964
Thereafter	$ 967,006
Minimum \| ES
Long-term Purchase Commitment [Line Items]
Storage and pipeline capacity, contract term	1 year
Maximum \| ES
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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