Derivative Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2020	Sep. 30, 2020
Derivatives, Fair Value
Derivative, notional amount	$ 350.0	$ 350.0
Accumulated other comprehensive income (loss), cumulative changes in net gain (loss) from cash flow hedges, before tax	(8.9)	(9.4)
Accumulated other comprehensive income (loss), cumulative changes in net gain (loss) from cash flow hedges, net of tax	(8.3)	(8.8)
Unrealized net gain (loss) on derivatives to be reclassified during next 12 months, net	(2.3)
Derivative asset, fair value, gross liability	9.2	10.4
Gain (loss), net on derivatives	(0.5)
Fair Value Adjustment
Derivatives, Fair Value
Gain (loss), net on derivatives	1.2
Net Cash Settlements
Derivatives, Fair Value
Gain (loss), net on derivatives	(1.2)
Reclassified from AOCI
Derivatives, Fair Value
Gain (loss), net on derivatives	(0.5)
Other current liabilities
Derivatives, Fair Value
Derivative asset, fair value, gross liability	4.7	4.6
Other noncurrent liabilities
Derivatives, Fair Value
Derivative asset, fair value, gross liability	4.5	5.8
Other liabilities
Derivatives, Fair Value
Derivative asset, fair value, gross liability	$ 9.2	$ 10.4

Accumulated Other Comprehensive Income, Cumulative Changes in Net Income (Loss) from Hedges, Before Tax

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Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges. Includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

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- Definition

Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset.

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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

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Nominal or face amount used to calculate payment on derivative.

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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.

+ References

No definition available.

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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.

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