Note 5 - Property And Equipment (Detail) (USD $)	3 Months Ended		6 Months Ended
	Nov. 30, 2012	Nov. 30, 2011	Nov. 30, 2012	Nov. 30, 2011
Depreciation	$ 5,200,000	$ 4,800,000	$ 10,100,000	$ 8,600,000
Gain (Loss) on Sale of Property Plant Equipment	(1,175,000)		(1,175,000)
Construction in Progress [Member]
Gain (Loss) on Sale of Property Plant Equipment	$ 1,200,000