Acquisitions - Schedule of Purchase Price Allocation (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Jul. 02, 2016	Jan. 01, 2016	Dec. 31, 2015	Sep. 11, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Estimated Fair Value, Goodwill	$ 613,335			$ 657,671		$ 650,778
Zindagi [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Goodwill			$ 10,503
Estimated Fair Value, Total			13,760
Zindagi [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Intangible assets			$ 3,257
PuzzleSocial [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Goodwill		$ 11,811
Estimated Fair Value, Total		20,429
Estimated Fair Value, Tangible net assets (liabilities) assumed		2,144
Deferred tax liabilities		(3,948)
PuzzleSocial [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Intangible assets		6,923
PuzzleSocial [Member] | Customer Base [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Intangible assets		$ 3,499
Rising Tide [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Goodwill					$ 25,050
Estimated Fair Value, Total					44,195
Estimated Fair Value, Tangible net assets (liabilities) assumed					2,445
Deferred tax liabilities					(10,300)
Rising Tide [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Estimated Fair Value, Intangible assets					$ 27,000