CONSOLIDATED BALANCE SHEETS - Parenthetical [Abstract] Statement [Table] Statement [Table] Statement, Scenario [Axis] Statement, Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Statement [Line Items] Statement [Line Items] LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity [Abstract] SHAREHOLDERS' EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Common stock, no par value (in dollars per share) Common Stock, No Par Value Common stock, authorized (in shares) Common Stock, Shares Authorized Common stock, issued (in shares) Common Stock, Shares, Issued Quarterly Financial Data (Unaudited) [Abstract] Quarterly Financial Data (Unaudited) [Abstract] Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Employee Benefit Plans [Abstract] Employee Benefit Plans [Abstract] Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income (loss) Net Income (Loss) Attributable to Parent Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation Depreciation Amortization Amortization of Intangible Assets Amortization of premium/discount on marketable securities Accretion (Amortization) of Discounts and Premiums, Investments Gain on sale of property and equipment Gain (Loss) on Sale of Property Plant Equipment Share-based compensation Share-based Compensation Excess tax benefits from share-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Equity in losses of affiliates Income (Loss) from Equity Method Investments Impairment of goodwill Goodwill, Impairment Loss Loss on sale of equity investees Gain (Loss) on Sale of Equity Investments Provision for doubtful accounts Provision for Doubtful Accounts Deferred income taxes, net Deferred Income Tax Expense (Benefit) Change in operating assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities CASH FLOWS FROM INVESTING ACTIVITIES: Net Cash Provided by (Used in) Investing Activities [Abstract] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Proceeds from sale of property and equipment Proceeds from Sale of Property, Plant, and Equipment Purchases of marketable securities Payments to Acquire Marketable Securities Sales or maturities of marketable securities Proceeds from Sale and Maturity of Marketable Securities Insurance recoveries on property and equipment Proceeds from Insurance Settlement, Investing Activities Other investing activities, net Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities CASH FLOWS FROM FINANCING ACTIVITIES: Net Cash Provided by (Used in) Financing Activities [Abstract] Borrowings on notes payable Proceeds from Lines of Credit Payments on notes payable Repayments of Notes Payable Proceeds from exercise of stock options Proceeds from Stock Options Exercised Excess tax benefits from share-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Principal payments on long-term obligations Repayments of Long-term Debt Dividends paid Payments of Dividends, Common Stock Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities EFFECT OF EXCHANGE RATE CHANGES ON CASH Effect of Exchange Rate on Cash and Cash Equivalents NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS Cash and Cash Equivalents, Period Increase (Decrease) CASH AND CASH EQUIVALENTS: Cash and Cash Equivalents [Abstract] Beginning of period Cash and Cash Equivalents, at Carrying Value End of period Income Statement [Abstract] Net sales Revenue, Net Cost of goods sold Cost of Revenue Gross profit Gross Profit Operating expenses: Operating Expenses [Abstract] Selling expense Selling Expense General and administrative General and Administrative Expense Product design and development Research and Development Expense Gain on insurance proceeds Insurance Recoveries Goodwill impairment Total operating expenses Operating Expenses Operating income (loss) Operating Income (Loss) Nonoperating income (expense): Nonoperating Income (Expense) [Abstract] Interest income Investment Income, Net Interest expense Interest Expense Other (expense) income, net Other Nonoperating Income (Expense) Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income tax expense (benefit) Income Tax Expense (Benefit) Net income (loss) Weighted average shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic Weighted Average Number of Shares Outstanding, Basic Diluted Weighted Average Number of Shares Outstanding, Diluted Earnings per share: Earnings Per Share [Abstract] Basic Earnings Per Share, Basic Diluted Earnings Per Share, Diluted Cash dividends paid per share Common Stock, Dividends, Per Share, Cash Paid Organization, Consolidation and Presentation of Financial Statements [Abstract] Nature of Business and Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Cash Flow Information [Abstract] Cash Flow Information [Abstract] Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Uncompleted Contracts [Abstract] Uncompleted Contracts [Abstract] Uncompleted Contracts Long-term Contracts or Programs Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Selected Financial Statement Data [Abstract] Selected Financial Statement Data [Abstract] Selected Financial Statement Data Additional Financial Information Disclosure [Text Block] Exit or Disposal Costs [Abstract] Exit or Disposal Costs [Abstract] Exit or Disposal Costs Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Entities [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Document Type Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Amendment Flag Entity Common Stock, Shares Outstanding Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Public Float Investments in Affiliates and Related Party Transactions [Abstract] Investments in Affiliates and Related Party Transactions [Abstract] Investments in Affiliates and Related Party Transactions Investments in and Advances to Affiliates, Schedule of Investments [Text Block] Financing Agreements [Abstract] Financing Agreements [Abstract] Financing Agreements Debt Disclosure [Text Block] Shareholders’ Equity and Share-Based Compensation [Abstract] Shareholders’ Equity and Share-Based Compensation [Abstract] Shareholders' Equity and Share-Based Compensation Shareholders' Equity and Share-based Payments [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Financial Information Derivative Instruments and Hedging Activities Disclosure [Text Block] Segment Reporting [Abstract] Segment Reporting Segment Reporting Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Long Lived Assets Goodwill and Intangible Assets Disclosure [Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] CURRENT ASSETS: Assets, Current [Abstract] Cash and cash equivalents Restricted cash Restricted Cash and Cash Equivalents, Current Marketable securities Available-for-sale Securities, Current Accounts receivable, net Accounts Receivable, Net, Current Inventories Inventory, Net Costs and estimated earnings in excess of billings Costs in Excess of Billings on Uncompleted Contracts or Programs Expected to be Collected within One Year Current maturities of long-term receivables Notes, Loans and Financing Receivable, Net, Current Prepaid expenses and other assets Prepaid Expense and Other Assets, Current Deferred income taxes Deferred Tax Assets, Net, Current Income tax receivables Income Taxes Receivable, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Advertising rights, net and other assets Advertising Rights Net And Other Cost of equipment is recorded as advertising rights where advertising agreements have not sold for the full value of the equipment at normal margins, reported on the balance sheet as noncurrent assets, and other assets not otherwise specified in the taxonomy. Long-term receivables, less current maturities Notes, Loans and Financing Receivable, Net, Noncurrent Goodwill Goodwill Intangible assets Intangible Assets, Net (Excluding Goodwill) Deferred income taxes Deferred Tax Assets, Net, Noncurrent TOTAL ASSETS Assets CURRENT LIABILITIES: Liabilities, Current [Abstract] Notes payable, bank Short-term Bank Loans and Notes Payable Accounts payable Accounts Payable, Current Accrued expenses Accrued Liabilities, Current Warranty obligations Product Warranty Accrual Billings in excess of costs and estimated earnings Billings in Excess of Cost, Current Customer deposits (billed or collected) Customer Deposits, Current Deferred revenue (billed or collected) Deferred Revenue, Current Current portion of other long-term obligations Long-term Debt, Current Maturities Income tax payable Accrued Income Taxes, Current Deferred income taxes Deferred Tax Liabilities, Current Total current liabilities Liabilities, Current Long-term warranty obligations Product Warranty Accrual, Noncurrent Long-term deferred revenue (billed or collected) Deferred Revenue, Noncurrent Other long-term obligations, less current maturities Other Liabilities, Noncurrent Deferred income taxes Deferred Tax Liabilities, Noncurrent Total long-term liabilities Liabilities, Noncurrent Common stock, no par value, authorized 120,000,000 shares; 41,930,116 and 41,606,070 shares issued at April 28, 2012 and April 30, 2011, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock, at cost, 19,680 shares Treasury Stock, Value Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Total Shareholders' Equity Stockholders' Equity Attributable to Parent TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity Receivables [Abstract] Receivables Financing Receivables [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Fair Value Disclosures [Abstract] Fair Value Measurements Fair Value Disclosures [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Statement of Stockholders' Equity [Abstract] Statement, Equity Components [Axis] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] Treasury Stock [Member] Treasury Stock [Member] Accumulated Other Comprehensive Income (Loss) [Member] Accumulated Other Comprehensive Income (Loss) [Member] Balance at Beginning of Period Net Income (loss) Foreign currency translation adjustment Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized gain on available for sale securities Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Net tax benefit (deduction) related to share compensation Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation Share-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Employee savings plan activity Stock Issued During Period, Value, Employee Stock Purchase Plan Dividends paid Dividends, Common Stock, Cash Balance at End of Period Marketable Securities [Abstract] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]