Components of Changes in Other Comprehensive Income (Loss) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended						3 Months Ended
	Aug. 31, 2013		Aug. 31, 2012	Aug. 31, 2013 Foreign Currency Translation	Aug. 31, 2013 Pension Liability Adjustment	May 31, 2013 Pension Liability Adjustment	Aug. 31, 2013 Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning balance	$ (12,036)			$ 4,025	$ (10,221)	$ (10,221)	$ (5,840)
Other comprehensive income before reclassifications	3,972			531			3,441
Reclassification adjustments to income	1,379	[1]					1,379	[1]
Income taxes	(1,469)		(157)				(1,469)
Accumulated other comprehensive loss, ending balance	$ (8,154)			$ 4,556	$ (10,221)	$ (10,221)	$ (2,489)

[1] The income statement classification of amounts reclassified to income for cash flow hedges is disclosed in "NOTE N - Derivative Instruments and Hedging Activities."