Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Maximum length of time hedged in price risk cash flow hedges.

+ References

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- Definition

Settlement on Derivative Instruments

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Nominal energy measure used to calculate payments on a derivative instrument.

+ References

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- Definition

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
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- Definition

Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 8
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Derivative Instruments and Hedging Activities - Additional Information (Details) kWh in Millions, MMBTU in Millions		12 Months Ended
	Mar. 31, 2016 USD ($)	Sep. 30, 2017 USD ($) MMBTU kWh	Sep. 30, 2016 USD ($) MMBTU kWh	Sep. 30, 2015 USD ($)
Derivative
Settlement of interest rate protection agreements	$ 35,975,000	$ 0	$ (35,975,000)	$ 0
Interest rate cash flow hedge loss to be reclassified during next 12 months, net		3,485,000
Restricted cash in brokerage accounts		3,046,000	583,000
Interest Rate Protection Agreements
Derivative
Underlying variable rate debt		$ 0	$ 0
Gas Utility
Derivative
Notional amount (in units) \| MMBTU		14.8	18.4
Maximum length of time hedged in price risk cash flow hedges (in months)		12 months
Electric Utility \| Electric Utility Electric Transmission Congestion
Derivative
Notional amount (in units) \| kWh		101.2	58.3
Maximum length of time hedged in price risk cash flow hedges (in months)		8 months