Changes to Contingent Consideration (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Business Acquisition, Contingent Consideration [Line Items]
Contingent consideration, beginning balance	$ 9,921
Increases due to acquisitions	18,585
Decrease due to payments	(7,223)
Changes due to currency fluctuations	987
Change in fair value of contingent consideration	591	(2,140)
Contingent consideration, ending balance	$ 22,861

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

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+ Details