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Stock-based Compensation Plans (Narrative) (Details) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2015 USD ($) $ / shares shares	Dec. 31, 2014 shares	Jun. 30, 2014 USD ($) shares	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($) shares	Sep. 30, 2014 $ / shares	Sep. 30, 2013 $ / shares
Allocated Share-based Compensation Expense	$ 0.6		$ 2.1	$ 5.9	$ 8.2
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 5.1			$ 5.1
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares	1,021,028		1,117,275	993,148	1,103,986
Phantom Share Units (PSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares		289,524
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Intrinsic Value, Amount Per Share | $ / shares	$ 9.10			$ 9.10
Share-based compensation liability	$ 2.7			$ 2.7
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares		240,691
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value | $ / shares	$ 9.78			$ 9.78		$ 8.52	$ 5.22
Cash-settled Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Share-based Liabilities Paid				$ 4.0
Minimum [Member] | Performance Shares [Member]
Performance Factor				0
Maximum [Member] | Performance Shares [Member]
Performance Factor				2

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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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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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Unrecognized cost of unvested share-based compensation awards.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Per share weighted average intrinsic value of equity-based compensation awards not vested. Excludes stock and unit options.

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Amount of cash paid related to share-based compensation liabilities.

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