Statement of Financial Position [Abstract] ASSETS: ASSETS: [Abstract] Current assets: Current assets: [Abstract] Cash and cash equivalents Marketable securities Accounts receivable, net of allowance for doubtful accounts of $326 at January 31, 2014 and $288 at April 30, 2013 Costs and estimated earnings in excess of billings, net Inventories Prepaid and 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 Cash surrender value of life insurance and cash held in trust Other assets Total assets LIABILITIES AND STOCKHOLDERS' EQUITY: LIABILITIES AND STOCKHOLDERS' EQUITY: [Abstract] Current liabilities: Current liabilities: [Abstract] Short-term credit obligations Accounts payable - trade Accrued liabilities Total current liabilities Long term debt- noncurrent Deferred compensation Deferred Rent And Other Long Term Liabilities Noncurrent Deferred rent and other liabilities Total liabilities Commitments and contingencies Stockholders' equity: Stockholders' equity: [Abstract] Preferred stock- $1.00 par value Common stock-$1.00 par value, issued 9,164 shares Additional paid-in capital Retained earnings Common stock reacquired and held in treasury – at cost (614 shares at January 31, 2014 and 701 shares at April 30, 2013) Accumulated other comprehensive income Total stockholders' equity Total liabilities and stockholders' equity Allowance for doubtful accounts Preferred stock, par value Common stock par value Common stock, shares issued Treasury stock, shares Income Statement [Abstract] Revenues Cost of revenues Gross margin Selling and administrative expenses Research and development expense Operating profit Other income (expense): Other income (expense): [Abstract] Investment income Interest expense Other income (expense), net Income before provision for income taxes Provision for income taxes Net income Net income per common share Net income per common share [Abstract] Basic (in Dollars per share) Diluted (in Dollars per share) Weighted average shares outstanding Weighted average shares outstanding [Abstract] Basic (in Shares) Diluted (in Shares) Condensed Consolidated Statements of Comprehensive Income Condensed Consolidated Statements of Comprehensive Income [Abstract] Net income Other comprehensive income: Other comprehensive income: [Abstract] Foreign currency translation adjustment Amount before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities. Change in market value of marketable securities Deferred tax effect of change in marketable securities Total other comprehensive income Comprehensive income Statement of Comprehensive Income [Abstract] Cash flows from operating activities: Cash flows from operating activities: [Abstract] Non-cash charges to earnings, net Gain on sale of equipment Net changes in operating assets and liabilities Net cash provided by operating activities Cash flows from investing activities: Cash flows from investing activities: [Abstract] Proceeds from sale of marketable securities Purchase of marketable securities Purchase of fixed assets Net cash used in investing activities Cash flows from financing activities: Cash flows from financing activities: [Abstract] Proceeds from credit line borrowings Payment of lease and short-term credit obligations Payment of cash dividend Tax benefit from exercise of stock-base compensation Exercise of stock options Net cash provided by (used in) financing activities Net increase in cash and cash equivalents before effect of exchange rate changes Effect of exchange rate changes on cash and cash equivalents Net increase in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Supplemental disclosures of cash flow information: Supplemental disclosures of cash flow information: [Abstract] Cash paid during the period for: Cash paid during the period for: [Abstract] Interest Income Taxes Disclosure Text Block [Abstract] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Earnings Per Share [Abstract] Earnings Per Share [Text Block] Contractors [Abstract] Long-term Contracts or Programs Disclosure [Text Block] Disclosure Text Block Supplement [Abstract] Treasury Stock [Text Block] Inventory Disclosure [Abstract] Inventory Disclosure [Text Block] Segment Reporting [Abstract] Segment Reporting Disclosure [Text Block] Investment Holdings [Abstract] Investment Holdings [Abstract] Investment Holdings [Text Block] Investments, Debt and Equity Securities [Abstract] Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Debt Disclosure [Abstract] Debt Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Tax Disclosure [Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Cost and Estimated Earnings on Uncompleted Contracts Costs and Estimated Earnings in Excess of Billings, Net [Table Text Block] Schedule of Inventory, Current [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] Available-for-sale Securities [Table Text Block] Unrealized Gain (Loss) on Investments [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted Schedule of Earnings Per Share, Basic and Diluted [Abstract] Weighted average shares outstanding: Weighted average shares outstanding: [Abstract] Basic Effect of dilutive securities Diluted Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Abstract] Outstanding options and SARS excluded Costs and Estimated Earnings in Excess of Billings, Net Costs and Estimated Earnings in Excess of Billings, Net [Abstract] Costs and estimated earnings in excess of billings Billings in excess of costs and estimated earnings Net asset Schedule of Inventory, Current Schedule of Inventory, Current [Abstract] Raw Materials and Component Parts Work in Progress Finished Goods Reconciliation of Operating Profit (Loss) from Segments to Consolidated Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Abstract] Segments [Domain] Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table] Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items] Revenues: Revenues: [Abstract] Revenues Operating profit (loss): Operating profit (loss): [Abstract] Operating profit (loss) Reconciliation of Assets from Segment to Consolidate Reconciliation of Assets from Segment to Consolidate [Abstract] Geographical [Domain] Reconciliation of Assets from Segment to Consolidated [Table] Segment Reporting, Asset Reconciling Item [Line Items] Identifiable assets Identifiable assets Available-for-sale Securities Available-for-sale Securities [Abstract] Fair Value, Option, Eligible Item or Group [Domain] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Line Items] Cost Gross Unrealized Gains Gross Unrealized Losses Fair Market Value Unrealized Gain (Loss) on Investments Unrealized Gain (Loss) on Investments [Abstract] Major Types of Debt and Equity Securities [Domain] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Unrealized Gain (Loss) on Investments [Table] NOTE H - FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - Unrealized Gain (Loss) on Investments [Line Items] 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 April 30, 2013 April 30, 2013 [Abstract] Fair Value, by Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Abstract] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Current Due after one year through five years Due after five years through ten years 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] Defined Contribution Plan Employer Discretionary Contribution, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Number contributions made by an employer to a defined contribution plan. NOTE E - INVENTORIES (Details) [Table] NOTE E - INVENTORIES (Details) [Line Items] Inventory, Net NOTE F - SEGMENT INFORMATION (Details) [Table] NOTE F - SEGMENT INFORMATION (Details) [Line Items] Number of Reportable Segments Number Of Principal Markets Number of Principal Markets Other Commitments [Domain] Investment [Domain] Revenue [Domain] NOTE G - INVESTMENT IN MORION, INC. (Details) [Table] NOTE G - INVESTMENT IN MORION, INC. (Details) [Line Items] Cost Method Investment Ownership Percentage Cost of Revenue Accounts Payable, Current Accounts Receivable, Net, Current Supply Commitment, Description Long-term Purchase Commitment, Description Proceeds from Deposits from Customers Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Cost Method Investment, Ownership Percentage Proceeds from Sale and Maturity of Marketable Securities Available-for-sale Securities, Gross Realized Gain (Loss) Debt Instrument, Name [Domain] Credit Facility [Domain] NOTE J - CREDIT FACILITY (Details) [Table] NOTE J - CREDIT FACILITY (Details) [Line Items] Line of Credit Facility, Maximum Borrowing Capacity Proceeds from Lines of Credit Long-term Debt, Excluding Current Maturities Line of Credit Facility, Borrowing Capacity, Description Line of Credit Facility, Collateral Line of Credit Facility, Interest Rate Description Debt Instrument, Maturity Date Line of Credit Facility, Commitment Fee Description Deferred Tax Assets, Valuation Allowance Other Commitments [Axis] Equity Securities [Member] Contracts Accounted for under Percentage of Completion [Member] Investment [Axis] Fixed Income Securities [Member] Credit Facility [Axis] Segments [Axis] Scenario [Axis] Geographical [Axis] Major Types of Debt and Equity Securities [Axis] Corporate Segment [Member] Change in Accounting Estimate by Type [Axis] Eligible Item or Group for Fair Value Option [Axis] Scenario, Unspecified [Domain] Debt Instrument [Axis] Revenue [Axis] Revenue [Axis] Revenue [Axis] Belgium [Member] Belgium [Member] Belgium [Member] China [Member] China [Member] China [Member] Former Financial Institution [Member] Former Financial Institution [Member] Former Financial Institution. Frequency Electronics Inc New York [Member] Frequency Electronics Inc New York [Member] Frequency Electronics Inc New York [Member] Frequency Electronics Inc Zyfer [Member] Frequency Electronics Inc Zyfer [Member] Frequency Electronics Inc Zyfer [Member] Gillam Frequency Electronics Inc [Member] Gillam Frequency Electronics Inc [Member] Gillam Frequency Electronics Inc [Member] Inter Segment [Member] Inter Segment [Member] Inter Segment [Member] JP Morgan Chase Bank [Member] JP Morgan Chase Bank [Member] JP Morgan Chase Bank. Line Of Credit Additional Amount Borrowed During The Period [Member] Line of Credit Additional Amount Borrowed During the Period [Member] Line of Credit Additional Amount Borrowed During the Period. Line Of Credit Borrowed On June 6_ 2013 [Member] Line of Credit Borrowed on June 6, 2013 [Member] Line of Credit Borrowed on June 6, 2013. Line Of Credit With Financial Institution [Member] Line of Credit with Financial Institution [Member] Line of Credit with Financial Institution [Member] Morion Inc Licensing Agreement [Member] Morion Inc. Licensing Agreement [Member] Morion Inc. Licensing Agreement [Member] Morion Inc [Member] Morion Inc [Member] Morion Inc [Member] Product And Training Services [Member] Product and Training Services [Member] Product and Training Services [Member] Technology Transfer Training And Sale Of Parts [Member] Technology Transfer, Training and Sale of Parts [Member] Technology Transfer, Training and Sale of Parts [Member] United States [Member] United States [Member] United States [Member] Document and Entity Information [Abstract] NumberOfPrincipalMarkets CostAndEstimatedEarningsOnUncompletedContractsTableTextBlock CostMethodInvestmentOwnershipPercentage DefinedContributionPlanEmployerDiscretionaryContributionShares Income Tax Disclosure [Text Block] Deferred Tax Assets, Net of Valuation Allowance, Current Entity Common Stock, Shares Outstanding Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net Cash Provided by (Used in) Operating Activities Liabilities, Current Available-for-sale Securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Payments to Acquire Property, Plant, and Equipment Segment Reporting Disclosure [Text Block] Payments to Acquire Marketable Securities Cash and Cash Equivalents, Period Increase (Decrease) Assets, Current Current Fiscal Year End Date Document Fiscal Period Focus Number of Reportable Segments Line of Credit Facility, Borrowing Capacity, Description Supply Commitment, Description Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Liabilities Long-term Purchase Commitment, Description Interest Expense Long-term Contracts or Programs Disclosure [Text Block] Line of Credit Facility, Commitment Fee Description Gross Profit Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Increase (Decrease) in Operating Capital Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Reconciliation of Assets from Segment to Consolidated [Table Text Block] Entity Well-known Seasoned Issuer Other Noncash Income (Expense) Line of Credit Facility, Interest Rate Description Entity Registrant Name Available-for-sale Securities [Table Text Block] Entity Voluntary Filers Assets Entity Public Float Entity Filer Category Net Cash Provided by (Used in) Financing Activities Deferred Tax Assets, Valuation Allowance New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Payments of Dividends Treasury Stock [Text Block] Entity Central Index Key Investment Holdings [Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Amendment Flag Stockholders' Equity before Treasury Stock Net Cash Provided by (Used in) Investing Activities Available-for-sale Securities, Gross Unrealized Loss Other Comprehensive Income (Loss), Net of Tax Line of Credit Facility, Collateral Billings in Excess of Cost Inventory Disclosure [Text Block] Document Period End Date Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Line of Credit Facility, Maximum Borrowing Capacity Stockholders' Equity Attributable to Parent Available-for-sale Securities, Gross Realized Gain (Loss) Schedule of Inventory, Current [Table Text Block] Amendment Description Unrealized Gain (Loss) on Investments [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Document Type Treasury Stock, Value Debt Disclosure [Text Block] Liabilities and Equity Proceeds from Deposits from Customers Entity Current Reporting Status Excess Tax Benefit from Share-based Compensation, Operating Activities Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Debt Instrument, Maturity Date Repayments of Short-term Debt Document Fiscal Year Focus Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Earnings Per Share [Text Block] Statement [Table] Statement [Line Items]