Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Taxes
Effective tax rate (as a percent)	30.00%		29.00%
Estimated effective tax rate (as a percent)		26.00%
Unrecognized tax benefits, exclusive of interest and penalties	$ 8.3		$ 8.3
Unrecognized tax benefits from permanent tax adjustments that, if recognized, would affect the effective rate	6.4
Estimated unrecognized tax benefits resulting from possible resolution of reviews by domestic and international taxing authorities	$ 4.9