Income Tax Expense - Carryforwards (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Net operating loss ("NOL") carry forwards
Federal net operating loss carry forwards	$ 144.1
State net operating loss carry forwards	36.3
Foreign net operating loss carry forwards	56.2
Period for which foreign NOL can be carried forward (in years)	10 years
Tax credit carry forwards
Foreign tax credit carry forwards	18.2
Research and development tax credit carry forwards	13.1
Alternative minimum tax credit carry forwards	2.1
State tax credits carry forward	$ 2.2