Note 8 - Changes In Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Feb. 29, 2016	May. 31, 2015
Balance at beginning of period	$ 842,258	$ 851,563
Additions:
Acquisition of businesses	346	432
Foreign currency translation adjustment	$ (1,763)	$ (9,737)
Impairment loss
Balance at end of period	$ 840,841	$ 842,258