Goodwill and Other Intangible Assets - Summary of Goodwill Activity (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 304,658
Addition	4,473
Foreign currency translation adjustment	(304)
Goodwill, ending balance	308,827
Search and Content
Goodwill [Roll Forward]
Goodwill, beginning balance	59,912
Addition	0
Foreign currency translation adjustment	0
Goodwill, ending balance	59,912
Tax Preparation
Goodwill [Roll Forward]
Goodwill, beginning balance	188,541
Addition	4,473
Foreign currency translation adjustment	(304)
Goodwill, ending balance	192,710
E-Commerce
Goodwill [Roll Forward]
Goodwill, beginning balance	56,205
Addition	0
Foreign currency translation adjustment	0
Goodwill, ending balance	$ 56,205