Summary of Significant Accounting Policies - Foreign Currency Translation (Details) (Other Expense, Net [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Other Expense, Net [Member]
Foreign Currency Translation [Line Items]
Net Foreign Currency Transaction Gains (Losses)	$ (1.6)	$ (1.1)	$ (1.1)