Summary of Significant Accounting Policies (Deferred Softward Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Deferred software costs	26.0us-gaap_CapitalizedComputerSoftwareNet	$ 23.8us-gaap_CapitalizedComputerSoftwareNet
Minimum \| Software and Software Development Costs
Useful lives	3 years
Maximum \| Software and Software Development Costs
Useful lives	5 years

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