Schedule of Financial Assets And Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)
In Thousands, unless otherwise specified
Feb. 28, 2014
May 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets $ 1,839 $ 761
Liabilities 4,964 9,774
Derivative Contracts
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets 1,839 [1] 761 [1]
Liabilities 4,654 [1] 9,774 [1]
Contingent consideration obligation
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Liabilities 310 [2]  
Significant Other Observable Inputs (Level 2)
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets 1,839 761
Liabilities 4,654 9,774
Significant Other Observable Inputs (Level 2) | Derivative Contracts
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Assets 1,839 [1] 761 [1]
Liabilities 4,654 [1] 9,774 [1]
Significant Unobservable Inputs (Level 3)
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Liabilities 310  
Significant Unobservable Inputs (Level 3) | Contingent consideration obligation
    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Liabilities $ 310 [2]  
[1] The fair value of our derivative contracts is based on the present value of the expected future cash flows considering the risks involved, including non-performance risk, and using discount rates appropriate for the respective maturities. Market observable, Level 2 inputs are used to determine the present value of the expected future cash flows. Refer to "NOTE O - Derivative Instruments and Hedging Activities" for additional information regarding our use of derivative instruments.
[2] The fair value of the contingent consideration obligation is determined using a Monte Carlo simulation model based on management's projections of future EBITDA levels. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement. At each reporting date, we will revalue the contingent consideration obligation to estimated fair value and record changes in fair value as income or expense in our consolidated statement of earnings.