Goodwill and Intangible Assets - Estimated Future Amortization of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jan. 31, 2015
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of fiscal 2015	$ 95,690
2016	92,056
2017	55,627
2018	40,298
2019	20,645
2020 and thereafter	25,669
IPR&D	2,400	[1]
Total	$ 332,385

[1] IPR&D projects are estimated to be completed within one year as of January 31, 2015. Assets are amortized over their useful life upon completion of the project or are written off upon abandonment.