NOTE D - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) - Costs and Estimated Earnings in Excess of Billings, Net - USD ($) $ in Thousands	Oct. 31, 2017	Apr. 30, 2017
Costs and Estimated Earnings in Excess of Billings, Net [Abstract]
Costs and estimated earnings in excess of billings	$ 6,205	$ 8,890
Billings in excess of costs and estimated earnings	(256)	(926)
Net asset	$ 5,949	$ 7,964