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Derivative Financial Instruments Narrative - USD ($) $ in Millions	3 Months Ended	6 Months Ended	60 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Sep. 30, 2021	Sep. 30, 2016
Derivative [Line Items]
Derivative, Cap Interest Rate				0.75%
Derivative, Fixed Interest Rate				2.341%
Derivative, Amount of Hedged Item				$ 150.0
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	$ 0.5	$ 1.1
Other current liabilities	1.4	1.4		2.0
Other noncurrent liabilities	0.7	0.7		5.3
Interest Rate Derivatives, at Fair Value, Net	(2.1)	(2.1)		(7.3)
Secured Debt [Member]
Derivative [Line Items]
Long-term Debt, Gross	$ 500.0	$ 500.0		$ 150.0
Debt Instrument, Interest Rate, Effective Percentage	4.58%	4.58%		4.841%
Debt Instrument, Basis Spread on Variable Rate		25000.00%
Scenario, Forecast [Member]
Derivative [Line Items]
HedgePeriodStart			Sep. 30, 2016
Derivative, Maturity Date			Sep. 30, 2021

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- Definition

Date on which a hedging relationship begins.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

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- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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- Definition

Amount of the hedged item as of the balance sheet date related to the derivative. For example, the hedged balance on a debt instrument.

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- Definition

Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract.

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- Definition

Fixed interest rate related to the interest rate derivative.

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Fair value, after the effects of master netting arrangements, of a financial liability or 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, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or 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, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

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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

Date the derivative contract matures, in CCYY-MM-DD format.

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The amount of net gains or losses on interest rate cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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Fair value as of the balance sheet date of interest rate derivative assets, net of interest rate derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized on the balance sheet.

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