Income Taxes - Additional Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Contingency [Line Items]
Effective income tax rate	2.40%	37.00%	0.40%	36.70%
Valuation allowance against net operating losses	$ 0.1		$ 0.1
Deferred tax assets, Valuation allowance	23.0		23.0		17.6
Uncertain tax position settled			2.1
Uncertain tax position against the statutes of limitation			$ 2.3