NOTE D - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) - Costs and Estimated Earnings in Excess of Billings, Net - USD ($) $ in Thousands	Jul. 31, 2018	Apr. 30, 2018
Costs and Estimated Earnings in Excess of Billings, Net [Abstract]
Costs and estimated earnings in excess of billings	$ 8,042	$ 5,266
Billings in excess of costs and estimated earnings	(1,310)	(172)
Net asset	$ 6,732	$ 5,094

Amount of receivable reflecting the cost incurred on uncompleted contracts in excess of related billings.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant