Goodwill and Intangible Assets - Estimated Future Amortization of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2015
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of fiscal 2015	$ 63,473
2016	93,294
2017	56,625
2018	40,552
2019	20,644
2020 and thereafter	25,668
IPR&D	2,400	[1]
Total	$ 302,656

[1] IPR&D projects are estimated to be completed within one year as of April 30, 2015. Assets are amortized over their useful life upon completion of the project or are written off upon abandonment.