Financial Instruments Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Other Comprehensive Income [Abstract]
Interest rate agreements	$ 43,184	$ 74,560
Forward commodity contracts	0	9,847
Interest rate agreements	1,752	662
Forward commodity contracts	0	(4,865)
Total other comprehensive income from hedging, net of tax	$ 44,936	$ 80,204
Expected Earnings [Line Items]
Income tax rate	23.00%
Interest rate agreements
Expected Earnings [Line Items]
FY2019	$ (1,863)
FY2020	(1,893)
FY2021	(1,893)
FY2022	(1,893)
FY2023	(1,893)
Thereafter	(38,729)
Total	$ (48,164)
Minimum
Expected Earnings [Line Items]
Income tax rate		37.00%
Maximum
Expected Earnings [Line Items]
Income tax rate		39.00%

Cash Flow Hedge Gain (Loss) To Be Recassiflied, Total

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Cash Flow Hedge Gain (Loss) To Be Reclassifed Year Two

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Cash Flow Hedge Gain (Loss) To Be Reclassified After Year Five

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Cash Flow Hedge Gain (Loss) To Be Reclassified Year Five

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Cash Flow Hedge Gain (Loss) To Be Reclassified Year Four

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Cash Flow Hedge Gain (Loss) To Be Reclassified Year Three

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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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Net of tax effect of the reclassification adjustment for accumulated gains and losses from forward commodity contracts designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period.

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No definition available.

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Net of tax effect of the reclassification adjustment for accumulated gains and losses from interest rate agreements designated and qualifying as the effective portion of cash flow hedges included in accumulated comprehensive income that was realized in net income during the period.

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Change in accumulated gains and losses from forward commodity contracts designated and qualifying as the effective portion of cash flow hedges, net of tax effect. The after tax effect change includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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Change in accumulated gains and losses from interest rate agreements designated and qualifying as the effective portion of cash flow hedges, net of tax effect. The after tax effect change includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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The domestic federal statutory tax rate applicable under enacted tax laws to the Regulated operations pretax income from continuing operations for the period. The "statutory" tax rate shall be the regular tax rate if there are alternative tax systems.

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669646-108580

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