Summary of Significant Accounting Policies (Deferred Softward Costs) (Details) (USD $) In Millions, unless otherwise specified			12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Minimum Software and Software Development Costs	Dec. 31, 2013 Maximum Software and Software Development Costs
Useful lives			3 years	5 years
Deferred software costs	$ 23.8	$ 17.1

The carrying amount of capitalized computer software costs net of accumulated amortization as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 985

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128487-111756

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 985

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756

Name:	us-gaap_CapitalizedComputerSoftwareNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant