Fair Value Measurements Maximum Remaining Potential Contingent Considertion (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Maximum Remaining Potential Contingent Consideration [Line Items]
Fair value of contingent consideration payable	$ 17,285	$ 17,738
Maximum remaining potential contingent consideration	$ 24,765

Fair value, as of the acquisition date, of potential payments under the contingent consideration arrangement including cash and shares.

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+ Details