Accounts Payable Current Accounts payable - trade Accounts Receivable Net Current Accounts receivable, net of allowance for doubtful accounts of $368 at January 31, 2012 and $258 at April 30, 2011 Accrued Liabilities Current Accrued liabilities Accumulated Other Comprehensive Income Loss Net Of Tax Accumulated other comprehensive income Additional Paid In Capital Additional paid-in capital Allowance For Doubtful Accounts Receivable Current Accounts receivable, allowance for doubtful accounts Amendment Flag Amendment Flag Asset Impairment Charges Impairment of investment in and loans receivable from affiliate Assets Total assets Assets [Abstract] ASSETS: Assets Current Total current assets Assets Current [Abstract] Current assets: Capital Lease Obligations Noncurrent Capital lease obligation- noncurrent Cash And Cash Equivalents At Carrying Value Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash and cash equivalents Cash And Cash Equivalents Period Increase Decrease Net decrease in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Before Adjustment Cash And Cash Equivalents Period Increase Decrease Before Adjustment Net decrease in cash and cash equivalents before effect of exchange rate changes Cash Paid During Period For [Abstract] Cash Paid During Period For [Abstract] Cash paid during the period for: Cash Surrender Value Of Life Insurance And Cash Held In Trust Cash Surrender Value Of Life Insurance And Cash Held In Trust Cash surrender value of life insurance and cash held in trust Commitments And Contingencies Commitments and contingencies Common Stock Par Or Stated Value Per Share Common stock, par value Common Stock Shares Issued Common stock, issued Common Stock Value Common stock - $1.00 par value, issued 9,163,940 shares Comprehensive Income Note [Text Block] COMPREHENSIVE INCOME Cost Of Revenue Cost of revenues Disclosure related to costs in excess of billings and billings in excess of costs incurred. Costs In Excess Of Billings And Billings In Excess Of Costs Incurred [Text Block] COSTS AND ESTIMATED EARNINGS IN EXCESS OF BILLINGS, NET Costs In Excess Of Billings On Uncompleted Contracts Or Programs Expected To Be Collected Within One Year Costs and estimated earnings in excess of billings, net Current Fiscal Year End Date Current Fiscal Year End Date Deferred Compensation Liability Classified Noncurrent Deferred compensation Deferred Rent And Other Long Term Liabilities Noncurrent Deferred Rent And Other Long Term Liabilities Noncurrent Deferred rent and other liabilities Deferred Tax Assets Net Current Deferred income taxes Deferred Tax Assets Net Noncurrent Deferred income taxes Description Of New Accounting Pronouncements Not Yet Adopted Recently Issued Accounting Pronouncements Document - Document and Entity Information [Abstract] Document Documentand Entity Information [Abstract] Document - Document and Entity Information [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Document Fiscal Year Focus Document Fiscal Year Focus Document Information [Line Items] Document Information [Line Items] Document Period End Date Document Period End Date Document Type Document Type Earnings Per Share [Abstract] Net income per common share Earnings Per Share Basic Basic Earnings Per Share Diluted Diluted Earnings Per Share [Text Block] EARNINGS PER SHARE Effect Of Exchange Rate On Cash And Cash Equivalents Effect of exchange rate changes on cash and cash equivalents Entities [Table] Entities [Table] Entity Central Index Key Entity Central Index Key Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Entity [Domain] Entity [Domain] Entity Filer Category Entity Filer Category Entity Registrant Name Entity Registrant Name Fair Value Disclosures [Text Block] FAIR VALUE OF FINANCIAL INSTRUMENTS Sum of the carrying amounts of all goodwill and intangible assets of the balance sheet date, net of accumulated amortization and impairment charges. Goodwill And Intangible Assets Net Goodwill and other intangible assets Gross Profit Gross margin Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest Income before provision for income taxes Income Loss From Equity Method Investments Equity (loss) income Income Statement [Abstract] Income Statement [Abstract] Income Tax Disclosure [Text Block] INCOME TAXES Income Taxes Paid Income Taxes Income Tax Expense Benefit Provision for income taxes Increase Decrease In Operating Capital Net changes in operating assets and liabilities Interest Expense Interest expense Interest Paid Interest Inventory Disclosure [Text Block] INVENTORIES Inventory Net Inventories Investment Income Interest Investment income Investments In Affiliates Subsidiaries Associates And Joint Ventures Investment in and loans receivable from affiliates Legal Entity [Axis] Legal Entity [Axis] Liabilities Total liabilities Liabilities And Stockholders Equity Total liabilities and stockholders' equity Liabilities And Stockholders Equity [Abstract] LIABILITIES AND STOCKHOLDERS' EQUITY: Liabilities Current Total current liabilities Liabilities Current [Abstract] Current liabilities: Marketable Securities Current Marketable securities Net Cash Provided By Used In Financing Activities Net cash provided by (used in) financing activities Net Cash Provided By Used In Financing Activities [Abstract] Cash flows from financing activities: Net Cash Provided By Used In Investing Activities Net cash used in investing activities Net Cash Provided By Used In Investing Activities [Abstract] Cash flows from investing activities: Net Cash Provided By Used In Operating Activities Net cash provided by operating activities Net Cash Provided By Used In Operating Activities [Abstract] Cash flows from operating activities: Net Income Loss Net income Net income Nonoperating Income Expense [Abstract] Other income (expense): Notes to Financial Statements [Abstract] Notes To Financial Statements [Abstract] Notes to Financial Statements [Abstract] Operating Income Loss Operating profit Organization Consolidation And Presentation Of Financial Statements Disclosure [Text Block] CONSOLIDATED FINANCIAL STATEMENTS Other Assets Noncurrent Other assets Other Noncash Income Expense Non-cash charges to earnings, net Other Nonoperating Income Expense Other expense, net Payments For Advance To Affiliate Loan to affiliate Payments To Acquire Marketable Securities Purchase of marketable securities Payments To Acquire Property Plant And Equipment Purchase of fixed assets Preferred Stock Par Or Stated Value Per Share Preferred stock, par value Preferred Stock Value Preferred stock - $1.00 par value Prepaid Expense And Other Assets Current Prepaid income taxes, expenses and other Proceeds From Sale And Maturity Of Marketable Securities Proceeds from sale of marketable securities Proceeds From Short Term Debt Proceeds from short-term credit obligations Proceeds From Stock Options Exercised Exercise of stock options Property Plant And Equipment Net Property, plant and equipment, at cost, less accumulated depreciation and amortization Related Party Transactions Disclosure [Text Block] RELATED PARTY TRANSACTIONS Repayments Of Debt Debt payments Research And Development Expense Research and development expense Retained Earnings Accumulated Deficit Retained earnings Revenues Revenues Segment Reporting Disclosure [Text Block] SEGMENT INFORMATION Selling General And Administrative Expense Selling and administrative expenses Short Term Borrowings Short-term credit obligations Statement [Line Items] Statement [Line Items] Statement Of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Statement Of Financial Position [Abstract] Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Stockholders Equity Total stockholders' equity Stockholders Equity [Abstract] Stockholders' equity: Stockholders Equity Before Treasury Stock Stockholders' Equity before Treasury Stock, Total Subsequent Events [Text Block] SUBSEQUENT EVENT- ACQUISITION OF ELCOM Supplemental Cash Flow Information [Abstract] Supplemental disclosures of cash flow information: Trading Symbol Trading Symbol Treasury Stock Shares Common stock reacquired and held in treasury, shares Treasury Stock [Text Block] TREASURY STOCK TRANSACTIONS Treasury Stock Value Common stock reacquired and held in treasury - at cost (817,317 shares at January 31, 2012 and 865,734 shares at April 30, 2011) Weighted Average Number Basic And Diluted, Shares Outstanding [Abstract] Weighted Average Number Basic And Diluted Shares Outstanding [Abstract] Weighted average shares outstanding Weighted Average Number Of Diluted Shares Outstanding Diluted Weighted Average Number Of Shares Outstanding Basic Basic