Certain Relationships and Related Party Transactions	12 Months Ended
Certain Relationships and Related Party Transactions	Dec. 31, 2012
Certain Relationships and Related Party Transactions
Certain Relationships and Related Party Transactions	10. Certain Relationships and Related Party Transactions William McBride, a Director of the Company, served as a member of the board of directors of AmeriGroup Corporation ("AmeriGroup"). The Company has a radiology benefits management agreement with a subsidiary of AmeriGroup under which the Company derived revenues of approximately $1.7 million, $1.8 million and $2.2 million in 2010, 2011 and 2012, respectively. In December 2012, Amerigroup was acquired by WellPoint, Inc. ("WellPoint"), with AmeriGroup operating as a wholly owned subsidiary within WellPoint. As a result, William McBride no longer serves as a member of the board of directors of AmeriGroup.

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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