NOTE D - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016
NOTE D - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) [Line Items]
Revenues	$ 9,337	$ 11,466	$ 21,360	$ 23,028
Contracts Accounted for under Percentage of Completion [Member]
NOTE D - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) [Line Items]
Revenues	$ 4,500	$ 5,100	$ 10,900	$ 12,400

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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