Equity- Additional Information (Detail) (USD $)	12 Months Ended
	May 31, 2012	May 31, 2011	May 31, 2010	Jun. 29, 2011 Maximum
Class of Stock [Line Items]
Common Stock shares authorized for repurchase				10,000,000
Common Stock remaining shares authorized for Repurchase	6,027,832
Repurchase of common shares	$ 73,418,000	$ 132,764,000
Purchases and retirement of common shares (in shares)	4,466,970	7,954,698
Net loss reclassified from AOCI for cash flow hedges	(1,245,000)	(2,431,000)	(2,219,000)
Net loss reclassified from AOCI for cash flow hedges, tax	794,000	1,487,000	1,222,000
Losses in accumulated other comprehensive income expected to be reclassified into net earnings	(1,135,000)
Losses in accumulated other comprehensive income expected to be reclassified into net earnings, tax	$ 724,000