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Stock-based Compensation Plans (Narrative) (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares	Mar. 31, 2015 USD ($) shares	Mar. 31, 2016 USD ($) $ / shares shares	Mar. 31, 2015 USD ($)
Allocated Share-based Compensation Expense | $	$ 2.1	$ 1.9	$ 4.5	$ 5.3
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | $	$ 6.4		$ 6.4
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,038,029	998,980	1,016,155
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value, Amount Per Share | $ / shares	$ 9.88		$ 9.88
Share-based compensation liability | $	$ 2.0		$ 2.0
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period			542,212
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			233,471
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			3 years
Share-based compensation, units awarded but not yet granted	235,876		235,876
Minimum [Member] | Performance Shares [Member]
Performance Factor			0
Maximum [Member] | Performance Shares [Member]
Performance Factor			2
Share-based Compensation Award, Tranche One [Member] | Performance Shares [Member]
Performance Factor			2
Share-based Compensation Award, Tranche Two [Member] | Performance Shares [Member]
Performance Factor			2
Share-based Compensation Award, Tranche Three [Member] | Performance Shares [Member]
Performance Factor			0

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Performance-based restricted stock units awarded by the Company for which performance criteria have not yet been set and related to future performance periods.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements.

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