Acquisitions - Summary of Allocation of Preliminary Purchase Price (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Nov. 16, 2015	Dec. 31, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Goodwill	$ 653,666		$ 124,142	$ 121,011
New World Systems Corporation [Member]
Business Acquisition [Line Items]
Cash		$ 22,486
Accounts receivable		37,098
Other current assets		2,371
Property and equipment		30,672
Identifiable intangible assets		264,814
Goodwill		527,618
Accounts payable		(1,382)
Accrued expenses		(7,282)
Deferred revenue		(53,098)
Deferred tax liabilities, net		(104,484)
Total consideration		$ 718,813