Segment Information (Details)	12 Months Ended
Apr. 30, 2021	Apr. 30, 2020
Segment Information (Details) [Line Items]
Number of Reportable Segments	2
Number of Operating Segments	2
Frequency Electronics Inc New York [Member]
Segment Information (Details) [Line Items]
Number Of Principal Markets	3
Customer Concentration Risk [Member] \| U.S. Government and U.S. Government Subcontractors [Member] \| Revenue Benchmark [Member]
Segment Information (Details) [Line Items]
Concentration Risk, Percentage	91.00%	83.00%

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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