Goodwill and Acquired Intangibles (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012
Changes in the carrying amount of goodwill
Balance as of December 31, 2011	$ 192,125
Effect of foreign currency translation	320
Balance as of March 31, 2012	$ 192,445

Carrying amount as of the balance sheet date, which is the cumulative amount paid and (if applicable) the fair value of any noncontrolling interest in the acquiree, adjusted for any amortization recognized prior to the adoption of any changes in generally accepted accounting principles (as applicable) and for any impairment charges, in excess of the fair value of net assets acquired in one or more business combination transactions.

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+ Details