Income Taxes - Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Effective income tax rate (percent)	38.20%	39.60%
Gross unrecognized tax benefit	$ 2.8		$ 2.7
Change in Unrecognized Tax Benefits Estimated in the Next Twelve Months	0.9
Accrued interest on income taxes	3.1		2.9
Accrued penalties on income taxes	0.1		0.1
Change in Unrecognized Tax Benefits	$ 0.2