Fair Value Totals and Balance Sheet Classification for Derivatives Designated as Hedges (Detail) (Long-term Debt, Designated as Hedging Instrument, Euro denominated long-term debt, USD $) In Thousands, unless otherwise specified	Aug. 31, 2014	May 31, 2014
Long-term Debt | Designated as Hedging Instrument | Euro denominated long-term debt
Derivatives, Fair Value [Line Items]
Fair value liability	$ 1,826	$ 1,229