Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	$ 629,330	$ 624,050
Amortized intangible assets, accumulated amortization	(444,919)	(403,854)
Indefinite-lived intangible assets (excluding goodwill)	357
Trade Names
Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	357	357
Developed Software and Core Technologies
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	336,715	336,262
Amortized intangible assets, accumulated amortization	(269,482)	(251,201)
Customer Lists and Contract Backlog
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	164,752	159,885
Amortized intangible assets, accumulated amortization	(88,554)	(76,160)
Trade Names
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	127,863	127,903
Amortized intangible assets, accumulated amortization	$ (86,883)	$ (76,493)