Concentrations of Credit Risk and Major Customers (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011 Customer	Dec. 31, 2010 Customer	Dec. 31, 2009 Customer
Concentration Risk
Concentration of risk, number of customers	5
Sales Revenue, Services, Net [Member] \| Customer Concentration Risk [Member]
Concentration Risk
Concentration of risk, number of customers	1	1	2
Concentration Risk, Percentage	38.00%	38.00%	40.00%
Entity-Wide Revenue, Major Customer, Amount	$ 69.3	$ 62.9	$ 109.9
Accounts Receivable [Member] \| Customer Concentration Risk [Member]
Concentration Risk
Concentration Risk, Percentage	32.00%	34.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13537-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13531-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

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Data Type:	num:percentItemType
Balance Type:	na
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