Contingent Liabilities (Details) (USD $)	3 Months Ended
	Aug. 31, 2011	Jul. 01, 2011
Contingent Liabilities
Breach of contract date	March 1, 2007
Cash consideration for acquisition of Bernz		$ 41,000,000
Reserves recognized prior to closing		14,402,000
Amount paid to resolve preexisting relationship with seller		$ 10,000,000