Income Taxes - Operating loss carryforwards (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
US Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 19.6	$ 0
Tax credit carryforwards	20.4	0
US State [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	135.6	0
Tax credit carryforwards	0.7	0
Foreign [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses	$ 67.1	$ 37.0