Annual report pursuant to Section 13 and 15(d)

Goodwill and Other Intangible Assets - Additional Information (Detail)

v2.4.0.6
Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]      
Amortization of finite-lived intangible assets $ 18,300,000 $ 16,200,000 $ 9,400,000
Payments to acquire domain names and other intangible assets 3,375,000 1,850,000  
Domain Names and Other Intangibles
     
Finite-Lived Intangible Assets [Line Items]      
Payments to acquire domain names and other intangible assets $ 400,000 $ 1,900,000