Note 11 - Derivative Financial Instruments (Details) - The Loss From Accumulated Other Comprehensive Income (Loss) (“OCI”) Into Income - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2015	Aug. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense (effective portion)	$ (217)	$ (261)
Interest Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest income (expense) (ineffective portion)	$ (1)