Contractual interest rate for funds borrowed, under the debt agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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DEBT - SCHEDULE OF LONG-TERM DEBT (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Jun. 21, 2016	Mar. 22, 2016
Debt Instrument [Line Items]
Total long-term debt	$ 1,180,619	$ 997,080
Natural Gas Distribution
Debt Instrument [Line Items]
Debt issuance costs	(6,515)	(6,262)
Less: Current maturities of long-term debt	(9,502)	(135,800)
Total long-term debt	691,965	569,642
Natural Gas Distribution \| First mortgage bonds: \| Series LL
Debt Instrument [Line Items]
Long-term debt	0	125,000
Natural Gas Distribution \| First mortgage bonds: \| Series MM
Debt Instrument [Line Items]
Long-term debt	9,545	9,545
Natural Gas Distribution \| First mortgage bonds: \| Series NN
Debt Instrument [Line Items]
Long-term debt	41,000	41,000
Natural Gas Distribution \| First mortgage bonds: \| Series OO
Debt Instrument [Line Items]
Long-term debt	46,500	46,500
Natural Gas Distribution \| First mortgage bonds: \| Series PP
Debt Instrument [Line Items]
Long-term debt	$ 50,000	50,000
Stated interest rate	3.15%
Natural Gas Distribution \| First mortgage bonds: \| Series QQ
Debt Instrument [Line Items]
Long-term debt	$ 70,000	70,000
Stated interest rate	3.58%
Natural Gas Distribution \| First mortgage bonds: \| Series RR
Debt Instrument [Line Items]
Long-term debt	$ 55,000	55,000
Stated interest rate	4.61%
Natural Gas Distribution \| First mortgage bonds: \| Series SS
Debt Instrument [Line Items]
Long-term debt	$ 50,000	50,000
Stated interest rate	2.82%
Natural Gas Distribution \| First mortgage bonds: \| Series TT
Debt Instrument [Line Items]
Long-term debt	$ 100,000	100,000
Stated interest rate	3.66%
Natural Gas Distribution \| First mortgage bonds: \| Series UU
Debt Instrument [Line Items]
Long-term debt	$ 125,000	125,000
Stated interest rate	3.63%		3.63%
Natural Gas Distribution \| First mortgage bonds: \| Series VV
Debt Instrument [Line Items]
Long-term debt	$ 125,000	0
Stated interest rate	4.01%
Natural Gas Distribution \| Capital lease obligations \| Capital lease obligation-buildings
Debt Instrument [Line Items]
Long-term debt	$ 8,749	11,617
Natural Gas Distribution \| Capital lease obligations \| Capital lease obligation-meters
Debt Instrument [Line Items]
Long-term debt	27,188	28,042
NJR
Debt Instrument [Line Items]
Debt issuance costs	(1,136)	(770)
Less: Current maturities of long-term debt	(100,000)	(25,000)
Total long-term debt	398,864	399,230
NJR \| Unsecured senior notes 2.51%
Debt Instrument [Line Items]
Long-term debt	$ 0	25,000
Stated interest rate	2.51%
NJR \| Unsecured senior notes 3.25%
Debt Instrument [Line Items]
Long-term debt	$ 50,000	50,000
Stated interest rate	3.25%
NJR \| Unsecured senior notes 3.48%
Debt Instrument [Line Items]
Long-term debt	$ 100,000	100,000
Stated interest rate	3.48%
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%
NJR \| Term loan \| Credit Agreement Due August 16, 2019
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	100,000	100,000
Clean Energy Ventures
Debt Instrument [Line Items]
Long-term debt	103,923	32,790
Less: Current maturities of long-term debt	(14,133)	(4,582)
Long-term debt, excluding current maturities	$ 89,790	$ 28,208