Note 8 - Goodwill (Details) - Changes in Goodwill - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	May. 31, 2014	May. 31, 2015	May. 31, 2014	May. 31, 2013
Changes in Goodwill [Abstract]
ABalance at beginning of period		$ 851,563	$ 1,003,463
Additions:
Acquisition of businesses		432	6,912
Foreign currency translation adjustment		(9,737)	1,188
Impairment loss	$ (160,000)	0	(160,000)	$ 0
Balance at end of period	$ 851,563	$ 842,258	$ 851,563	$ 1,003,463