Goodwill and Intangible Assets (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended
Jun. 30, 2012
Summary of goodwill activity  
Balance, December 31, 2011 $ 595,522
Acquisition of certain assets and liabilities of various entities 2,100
Adjustment during the measurement period relating to the acquisition of InsWeb Corporation 559
Balance, June 30, 2012 $ 598,181