Income Taxes - Narrative (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Effective income tax rate (percent)	37.80%	38.20%
Gross unrecognized tax benefit	$ 3.1		$ 2.7
Expected change in unrecognized tax benefits	0.7
Accrued interest on income taxes	3.7		2.9
Accrued penalties on income taxes	0.1		0.1
Change in Unrecognized Tax Benefits	$ 0.8