NOTE C - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) - Costs and Estimated Earnings in Excess of Billings, Net - USD ($) $ in Thousands	Jan. 31, 2016	Apr. 30, 2015
Costs and Estimated Earnings in Excess of Billings, Net [Abstract]
Costs and estimated earnings in excess of billings	$ 12,640	$ 14,057
Billings in excess of costs and estimated earnings	(295)	(1,128)
Net asset	$ 12,345	$ 12,929