Goodwill and Other Intangible Assets - Summary of Goodwill Activity (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Goodwill [Line Items]    
Goodwill, net $ 304,658 $ 304,658
Search and Content    
Goodwill [Line Items]    
Goodwill, net 59,912 59,912
Tax Preparation    
Goodwill [Line Items]    
Goodwill, net 188,541 188,541
E-Commerce    
Goodwill [Line Items]    
Goodwill, net $ 56,205 $ 56,205