Note 15 - Segment Reporting and Sales by Major Customer - Schedule of Revenue by Major Customers by Reporting Segments (Details)	3 Months Ended
Jul. 31, 2022	Jul. 31, 2021
Revenue Benchmark [Member] \| Customer Concentration Risk [Member] \| Aerospace Products [Member]
Aerospace Products – one customer in the three months ended July 31, 2022, one customer in the three months ended July 31, 2021	11.70%	10.70%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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