Sale Leaseback Transaction, Net Proceeds, Financing Activities, Solar

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Sale Leaseback Transaction, Term Of Lease

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DEBT - NJR LONG-TERM DEBT (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Jan. 26, 2018	Mar. 22, 2016
Debt Instrument [Line Items]
Proceeds from sale-leaseback transaction - solar	$ 71,538	$ 32,901	$ 0
Clean Energy Ventures
Debt Instrument [Line Items]
Proceeds from sale-leaseback transaction - solar	71,538	32,901
Interest rate swap
Debt Instrument [Line Items]
Fixed treasury rate				2.84%
Interest rate swap \| Credit Agreement Due August 16, 2019 \| Term loan
Debt Instrument [Line Items]
Long-term debt				$ 100,000
NJR \| Unsecured senior notes 3.20%
Debt Instrument [Line Items]
Long-term debt	50,000	50,000
Stated interest rate					3.20%
NJR \| Unsecured senior notes 3.54%
Debt Instrument [Line Items]
Long-term debt	100,000	100,000
Stated interest rate					3.54%
NJR \| Unsecured senior notes 3.96%
Debt Instrument [Line Items]
Long-term debt	$ 100,000	$ 0
Stated interest rate					3.96%
Minimum \| Clean Energy Ventures
Debt Instrument [Line Items]
Term of lease	6 years
Maximum \| Clean Energy Ventures
Debt Instrument [Line Items]
Term of lease	15 years