Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Effective tax rate	34.90%	37.90%	37.90%	39.00%
Income tax benefit related to expiration of statute of limitations for uncertain tax positions and adjustment to prior year estimate	$ 0.7	$ 0.3	$ 0.7	$ 0.5
Effective income tax rate reconciliation, expiration of statute of limitations for uncertain tax positions and adjustment of prior year estimate	4.30%	2.00%	1.70%	1.20%
Total gross amount of unrecognized tax benefits that would impact effective tax rate	0.7		0.7		1.6
Potential impact on total gross amount of unrecognized tax benefits	$ 0.3		$ 0.3