PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	Jan. 31, 2018	Apr. 30, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 34,398	$ 34,345
Less accumulated depreciation	(24,370)	(23,493)
Property, plant and equipment, net	10,028	10,852
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	15,925	15,995
Furniture and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 18,473	$ 18,350