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Debt - Effective Interest Rate (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Debt
Effective interest rate including effects of interest rate swap agreements			4.6%	4.4%
Amortization of deferred debt issuance costs	$ 2.5	$ 2.8	$ 15.1	$ 14.3
The 2022 Notes
Debt
Prepayment premium redemption	$ 34.5		$ 34.5

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Amount of amortization expense attributable to debt issuance costs.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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Description of any adjustments made to the stated rate to determine the effective rate.

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-Topic 210
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