Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Amortization of Capitalized Software	$ 2.2	$ 1.4	$ 1.3
Impairment of Long-Lived Assets to be Disposed of				$ 0.6	$ 0	$ 0
Property and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives				3 years
Property and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives				7 years
Software | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives				1 year
Software | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives				3 years