Note 7 - Goodwill (Details) - Changes in Goodwill (USD $)	3 Months Ended	12 Months Ended
	May 31, 2014	May 31, 2014	May 31, 2013	May 31, 2012
Changes in Goodwill [Abstract]
Balance at beginning of period		$ 1,003,463,000	$ 966,338,000
Additions:
Acquisition of businesses		6,912,000	36,889,000
Foreign currency translation adjustment		1,188,000	236,000
Impairment loss	(160,000,000)	(160,000,000)	0	0
Balance at end of period	$ 851,563,000	$ 851,563,000	$ 1,003,463,000	$ 966,338,000