Summary of Significant Accounting Policies (Details 4) (Deferred Software Costs, USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011 Y	Dec. 31, 2010
Deferred Software Costs
Information related to deferred software costs
Estimated useful life over which cost will be amortized, minimum (in years)	3
Estimated useful life over which cost will be amortized, maximum (in years)	5
Unamortized deferred software costs	$ 22.8	$ 18.1

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 Implementation Guide (Q and A)

-Number FAS86

-Paragraph 18

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 86

-Paragraph 11

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: 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

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Period Type:	instant