Acquisitions - Schedule of Purchase Price Allocation (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 11, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 667,195		$ 650,778
Rising Tide Games [Member]
Business Acquisition [Line Items]
Net tangible assets acquired (liabilities assumed)		$ 2,445
Goodwill		25,050
Deferred tax liabilities		(10,300)
Total		44,195
Rising Tide Games [Member] | Developed technology [Member]
Business Acquisition [Line Items]
Fair Value, Intangible assets		$ 27,000