Income Taxes - Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Tax Contingency [Line Items]
Effective income tax rate	9.00%	14.00%	16.00%	13.00%
Statutory income tax rate			35.00%
Unrecognized tax benefits	$ 12.0		$ 12.0
Unrecognized tax benefits that would impact the effective tax rate	12.0		12.0
Other long-term liabilities
Income Tax Contingency [Line Items]
Estimated accrued interest and penalties	$ 3.2		$ 3.2