Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Income Taxes
Effective tax rate (as a percent)	32.50%	27.60%	32.30%	27.50%
Unrecognized tax benefits	$ 0.2		$ 0.2