Deferred compensation arrangement percentage of participants compensation deferred.

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- Definition

Net deferred gain net of taxes expected to be recognized in interest expense.

+ References

No definition available.

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- Definition

Net deferred losses net of taxes expected to be recognized in interest expense.

+ References

No definition available.

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- Definition

Number of outstanding fuel contracts.

+ References

No definition available.

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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.

+ References

No definition available.

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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

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Fair Value Measurements and Derivative Instruments - Additional Information (Details)	3 Months Ended	6 Months Ended
	Mar. 31, 2021 USD ($) Fuel	Mar. 31, 2021 USD ($) Fuel gal	Sep. 30, 2020 USD ($)
Interest Rate Contracts
Derivative [Line Items]
Notional amount	$ 500,000,000.0	$ 500,000,000.0	$ 980,000,000.0
Interest Rate Swaps
Derivative [Line Items]
Net deferred losses on interest rate swap net of taxes expected to be recognized over the next 12 months	$ 2,200,000
Fuel Swap Contracts
Derivative [Line Items]
Number of outstanding fuel contracts \| Fuel	2	2
Notional volume \| gal		5,300,000
Net deferred gain on fuel swap net of taxes expected to be recognized over the next 12 months		$ 1,700,000
Maximum
Derivative [Line Items]
Percentage of participants compensation deferred		70.00%