Statement of Financial Position [Abstract] Cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Marketable securities Accounts receivable, net of allowance for doubtful accounts of $216 at July 31, 2014 and $234 at April 30, 2014 Allowance for doubtful accounts Costs and estimated earnings in excess of billings, net Net asset Inventories Inventory, Net Deferred income taxes Prepaid expenses and other Total current assets Property, plant and equipment, at cost, less accumulated depreciation and amortization Deferred income taxes Goodwill and other intangible assets Cash surrender value of life insurance and cash held in trust Other assets Total assets Identifiable assets Accounts payable - trade Accrued liabilities Total current liabilities Long term debt- noncurrent Deferred compensation Deferred rent and other liabilities Total liabilities Commitments and contingencies Preferred stock- $1.00 par value Preferred stock- par value Common stock-$1.00 par value, issued 9,164 shares Common stock, par value Common stock, shares issued Additional paid-in capital Retained earnings Common stock reacquired and held in treasury - at cost (574 shares at July 31, 2014 and 593 shares at April 30, 2014) Treasury stock, shares Accumulated other comprehensive income Total stockholders' equity Total liabilities and stockholders' equity Income Statement [Abstract] Net revenues Revenues Cost of revenues Gross margin Selling and administrative expenses Research and development expense Operating profit Operating profit (loss) Investment income Interest expense Other income, net Income before provision for income taxes Provision for income taxes Net income Net income Basic (in Dollars per share) Diluted (in Dollars per share) Basic (in Shares) Basic EPS Shares outstanding (weighted average) Diluted (in Shares) Diluted EPS Shares outstanding Foreign currency translation adjustment Change in market value of marketable securities before reclassification, net of tax of ($139) and $189 Change in market value of marketable securities before reclassification, tax Reclassification adjustment for realized gains included in net income, net of tax of $95 and $0 Reclassification adjustment for realized gains included in net income, tax Total unrealized gain (loss) on marketable securities, net of tax Total other comprehensive income (loss) Comprehensive income Statement of Comprehensive Income [Abstract] Non-cash charges to earnings, net Net changes in operating assets and liabilities Net cash used in operating activities Purchase of marketable securities Proceeds on redemption of marketable securities Proceeds from Sale and Maturity of Marketable Securities Purchase of fixed assets Net cash provided by (used in) investing activities Borrowings from long-term credit facility Tax benefit from exercise of stock-based compensation Payment of lease obligations Net cash provided by financing activities Net (decrease) increase in cash and cash equivalents before effect of exchange rate changes Effect of exchange rate changes on cash and cash equivalents Net (decrease) increase in cash and cash equivalents Interest Income Taxes Disclosure Text Block [Abstract] Earnings Per Share [Abstract] Schedule of Weighted Average Number of Shares [Abstract] Contractors [Abstract] Costs in Excess of Billings and Billings in Excess of Costs [Abstract] Costs and estimated earnings in excess of billings Billings in excess of costs and estimated earnings Disclosure Text Block Supplement [Abstract] Inventory Disclosure [Abstract] Schedule of Inventory, Current [Abstract] Raw Materials and Component Parts Work in Progress Finished Goods Segment Reporting [Abstract] Reconciliation of Revenue from Segments to Consolidated [Abstract] Consolidation Items [Axis] Operating Segments [Member] Segments [Axis] Frequency Electronics Inc New York [Member] Gillam Frequency Electronics Inc [Member] Frequency Electronics Inc Zyfer [Member] Intersegment Eliminations [Member] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract] Corporate, Non-Segment [Member] Reconciliation of Assets from Segment to Consolidate [Abstract] Geographical [Axis] CHINA Identifiable assets Investment Holdings [Text Block] [Abstract] Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities Reconciliation [Abstract] Eligible Item or Group for Fair Value Option [Axis] Fixed Income Securities [Member] Cost Gross Unrealized Gains Gross Unrealized Losses Fair Market Value Equity Securities [Member] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract] Major Types of Debt and Equity Securities [Axis] Fair Value, Less than 12 months Unrealized Losses, Less than 12 months Fair Value, 12 Months or More Unrealized Losses, 12 Months or More Fair Value Unrealized Losses Investments Classified by Contractual Maturity Date [Abstract] Current Due after one year through five years Due after five years through ten years New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Debt Disclosure [Abstract] Income Tax Disclosure [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Earnings Per Share [Text Block] Schedule of Weighted Average Number of Shares [Table Text Block] Effect of Dilutive Securities Long-term Contracts or Programs Disclosure [Text Block] Costs in Excess of Billings and Billings in Excess of Costs [Table Text Block] Treasury Stock [Text Block] Inventory Disclosure [Text Block] Schedule of Inventory, Current [Table Text Block] Segment Reporting Disclosure [Text Block] Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Reconciliation of Assets from Segment to Consolidated [Table Text Block] Investment Holdings [Text Block] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Schedule of Available-for-sale Securities Reconciliation [Table Text Block] Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block] Investments Classified by Contractual Maturity Date [Table Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Debt Disclosure [Text Block] Income Tax Disclosure [Text Block] Change in Accounting Estimate by Type [Axis] Contracts Accounted for under Percentage of Completion [Member] UNITED STATES BELGIUM Investment [Axis] Morion Inc [Member] Other Commitments [Axis] License Agreement [Member] Long-term Debt, Type [Axis] Line of Credit [Member] Debt Instrument [Axis] Debt Instrument, Tranche B [Member] Debt Instrument, Tranche A [Member] Variable Rate [Axis] London Interbank Offered Rate (LIBOR) [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Defined Contribution Plan Employer Discretionary Contribution, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Number of Reportable Segments Number Of Principal Markets Cost Method Investment Ownership Percentage Related Party Transaction, Purchases from Related Party Revenue from Related Parties Accounts Receivable, Related Parties, Current Accounts Payable, Related Parties, Current Long-term Purchase Commitment, Description License And Equipment Fee Receivable Percentage Of Royalties Payable On Third Party Sales Long-term Purchase Commitment, Period Purchase Commitment, Remaining Minimum Amount Committed Proceeds from Deposits from Customers Available-for-sale Securities, Gross Realized Gain (Loss) Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Borrowing Capacity, Description Long-term Line of Credit, Noncurrent Line of Credit Facility, Collateral Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Maturity Date Line of Credit Facility, Commitment Fee Percentage Deferred Tax Assets, Valuation Allowance ASSETS: Current assets: LIABILITIES AND STOCKHOLDERS' EQUITY: Current liabilities: Stockholders' equity: Other income (expense): Net income per common share: Average shares outstanding: Condensed Consolidated Statements of Comprehensive Income Other comprehensive income (loss): Unrealized gain (loss) on marketable securities: Cash flows from operating activities: Cash flows from investing activities: Cash flows from financing activities: Supplemental disclosures of cash flow information: Cash paid during the period for: Consolidation Items [Domain] Segments [Domain] Reconciliation of Revenue from Segments to Consolidated [Table] Segment Reporting, Revenue Reconciling Item [Line Items] Net revenues: Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Operating profit (loss): Geographical [Domain] Reconciliation of Assets from Segment to Consolidated [Table] Segment Reporting, Asset Reconciling Item [Line Items] Identifiable assets: Fair Value, Option, Eligible Item or Group [Domain] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Schedule of Available-for-sale Securities Reconciliation [Table] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Schedule of Available-for-sale Securities Reconciliation [Line Items] Major Types of Debt and Equity Securities [Domain] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Line Items] April 30, 2014 NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Investments Classified by Contractual Maturity Date [Table] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Investments Classified by Contractual Maturity Date [Line Items] Change in Accounting Estimate, Type [Domain] NOTE C - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) [Table] NOTE C - COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET (Details) [Line Items] NOTE E - INVENTORIES (Details) [Table] NOTE E - INVENTORIES (Details) [Line Items] NOTE F - SEGMENT INFORMATION (Details) [Table] NOTE F - SEGMENT INFORMATION (Details) [Line Items] Other Commitments [Domain] Investment [Domain] NOTE G - INVESTMENT IN MORION, INC. (Details) [Table] NOTE G - INVESTMENT IN MORION, INC. (Details) [Line Items] Debt Instrument, Name [Domain] Long-term Debt, Type [Domain] Variable Rate [Domain] NOTE J - CREDIT FACILITY (Details) [Table] NOTE J - CREDIT FACILITY (Details) [Line Items] Cost Method Investment, Ownership Percentage Number contributions made by an employer to a defined contribution plan. License And Equipment Fee Receivable This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity and the amount of investment interest and dividend income on marketable securities. Number of Principal Markets Aggregate carrying amount, as of the balance sheet date, of noncurrent obligations not separately disclosed in the balance sheet and the cumulative difference between the rental income or payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other. Noncurrent liabilities are expected to be paid after one year (or the normal operating cycle, if longer). Percentage of royalties payable on third party sales Debt Instrument Tranche A [Member] Debt Instrument, Tranche A. Debt Instrument Tranche B [Member] Debt Instrument, Tranche B. Frequency Electronics Inc New York [Member] Frequency Electronics Inc New York [Member] Frequency Electronics Inc Zyfer [Member] Frequency Electronics Inc Zyfer [Member] Gillam Frequency Electronics Inc [Member] Gillam Frequency Electronics Inc [Member] License Agreement [Member] License Agreement. Morion Inc [Member] Morion Inc [Member] Document and Entity Information [Abstract] April302014Abstract NetIncomePerCommonShareAbstract IdentifiableAssetsAbstract AverageSharesOutstandingAbstract CashPaidDuringThePeriodForAbstract CashFlowsFromInvestingActivitiesAbstract CashFlowsFromOperatingActivitiesAbstract CondensedConsolidatedStatementsOfComprehensiveIncomeAbstract OtherIncomeExpenseAbstract CurrentAssetsAbstract CurrentLiabilitiesAbstract CashFlowsFromFinancingActivitiesAbstract SupplementalDisclosuresOfCashFlowInformationAbstract UnrealizedGainLossOnMarketableSecuritiesAbstract OperatingProfitLossAbstract NetRevenuesAbstract OtherComprehensiveIncomeLossAbstract Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax Payments to Acquire Marketable Securities Cash and Cash Equivalents, Period Increase (Decrease) Assets, Current Payments to Acquire Property, Plant, and Equipment Available-for-sale Securities Liabilities, Current Net Cash Provided by (Used in) Operating Activities Comprehensive Income (Loss), Net of Tax, Attributable to Parent Deferred Tax Assets, Net of Valuation Allowance, Current Entity Common Stock, Shares Outstanding Repayments of Debt and Capital Lease Obligations Assets Entity Well-known Seasoned Issuer Entity Registrant Name Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Entity Voluntary Filers Entity Filer Category Entity Public Float Other Noncash Income (Expense) Gross Profit Document Fiscal Period Focus Current Fiscal Year End Date Increase (Decrease) in Operating Capital Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Liabilities Interest Expense Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Amendment Flag Billings in Excess of Cost Other Comprehensive Income (Loss), Net of Tax Document Period End Date Stockholders' Equity before Treasury Stock Other Assets Available-for-sale Securities, Gross Unrealized Loss Net Cash Provided by (Used in) Investing Activities Stockholders' Equity Attributable to Parent [Abstract] Entity Central Index Key Net Cash Provided by (Used in) Financing Activities Liabilities and Equity [Abstract] Assets [Abstract] Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Entity Current Reporting Status Excess Tax Benefit from Share-based Compensation, Operating Activities Document Fiscal Year Focus Liabilities and Equity Treasury Stock, Value Amendment Description Document Type Stockholders' Equity Attributable to Parent Statement [Table] Statement [Line Items] Scenario [Axis]