Quarterly Financial Information Disclosure [Abstract] Net sales Revenue, Net Gross profit Gross Profit Net income (loss) Net Income (Loss) Attributable to Parent Basic earnings (loss) per share (in dollars per share) Earnings Per Share, Basic Diluted earnings (loss) per share (in dollars per share) Earnings Per Share, Diluted Changes in accrued warranty costs for pre-existing warranties during the period, including expirations Standard and Extended Product Warranty Accrual, Increase (Decrease) for Preexisting Warranties Impact of Tax Act Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Debt Disclosure [Abstract] Financing Agreements Debt Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Contractors [Abstract] Uncompleted Contracts Long-term Contracts or Programs Disclosure [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Sales returns, reserve Revenue Recognition, Sales Returns, Reserve for Sales Returns Percentage of net sales from long-term construction-type contracts Sales Revenue, Long-term Construction-type Contracts, Net, Percentage The percentage of net long-term construction-type contract revenue to total net revenue from the sale of long-term construction-type contracts as of year end. Percentage of net sales from equipment contracts Sales Revenue, Equipment Contracts, Net, Percentage The percentage of net equipment contract revenue to total net revenue from the sale of equipment contracts as of year end. Deferred revenue period for recognition of product maintenance contracts Revenue Recognition, Period of Deferred Revenue Recognition Revenue Recognition, Period of Deferred Revenue Recognition Deferred Revenue Deferred Revenue Percentage of net sales from services Sales Revenue, Services, Net, Percentage The percentage of net service revenue to total net revenue from the sale of services as of year end. Selected Financial Statement Data [Abstract] Selected Financial Statement Data [Abstract] Foreign currency transaction losses Foreign Currency Transaction Gain (Loss), before Tax Equity in losses of affiliate Income (Loss) from Equity Method Investments Other Nonoperating Expense Other Nonoperating Expense Other Other Nonoperating Income Other (expense) income, net Other Nonoperating Income (Expense) Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Commerical Commerical [Member] Commerical [Member] Live Events Live Events [Member] Live Events [Member] High School Park and Recreation High School Park and Recreation [Member] High School Park and Recreation [Member] Transportation Transportation [Member] Transportation [Member] International International [Member] International [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Goodwill Goodwill [Line Items] Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount Reporting Unit, Percentage of Fair Value in Excess of Carrying Amount Impairment of intangible assets Impairment of Intangible Assets, Finite-lived Amortization of Intangible Assets Amortization of Intangible Assets Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Additional Paid-In Capital Additional Paid-in Capital [Member] Retained Earnings Retained Earnings [Member] Treasury Stock Treasury Stock [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance at Beginning of Period Stockholders' Equity Attributable to Parent Net income Cumulative translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized (loss) gain on available-for-sale securities, net of tax Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Net tax benefit related to share-based 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 Tax payments related to RSU Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Employee savings plan activity Stock Issued During Period, Value, Employee Stock Purchase Plan Dividends paid Dividends, Common Stock, Cash Treasury stock purchase Treasury Stock, Value, Acquired, Cost Method Balance at End of Period Nature of Business and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Operating Segments [Member] Operating Segments [Member] Unallocated corporate depreciation Segment Reconciling Items [Member] Segment Reporting Information Segment Reporting Information [Line Items] Number of business units Number of Reportable Segments Contribution Margin Contribution Margin Contribution Margin Non-allocated operating expenses: Operating Expenses [Abstract] General and administrative General and Administrative Expense Product design and development Research and Development Expense Operating income Operating Income (Loss) Nonoperating income (expense): Nonoperating Income (Expense) [Abstract] Interest income Investment Income, Net Interest expense Interest Expense Other (expense) income, net Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Depreciation, amortization, and impairment Depreciation, Depletion and Amortization, Nonproduction Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Estimate of Fair Value Measurement Estimate of Fair Value Measurement [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Recurring Basis Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets (Liability), net Fair Value, Net Asset (Liability) Sensitivity analysis of fair value, fair value, net asset (liability), impact of change in assumption Sensitivity Analysis of Fair Value, Fair Value, Net Asset (Liability), Impact of Change in Assumption Sensitivity Analysis of Fair Value, Fair Value, Net Asset (Liability), Impact of Change in Assumption Computed income tax expense at federal, state and local jurisdiction statutory rates Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Research and development tax credit Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount State taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Other, net Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Change in valuation allowances Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Stock compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Meals and entertainment Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment, Amount Domestic production activities deduction Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Amount Dividends paid to retirement plan Effective Income Tax Rate Reconciliation, Deduction, Employee Stock Ownership Plan Dividend, Amount Change in uncertain tax positions Effective Income Tax Rate Reconciliation, Tax Contingency, Amount Income tax expense Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Stock Options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Outstanding at beginning of year, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Granted, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Canceled or forfeited, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Exercised, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Outstanding at end of year, Shares Shares vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Exercisable at end of year, Shares Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Weighted Average Exercise Price Per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Outstanding at beginning of year, (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Granted, (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Canceled or forfeited, (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Exercised, (usd per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Outstanding at end of year, (usd per share) Shares vested and expected to vest (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Exercisable at end of year (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Outstanding, beginning of period, weighted average remaining contractual life Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Outstanding, end of period, weighted average remaining contractual life Vested and expected to vest, weighted average remaining contractual life Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Exercisable at end of period, weighted average remaining contractual life Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Outstanding, beginning of period, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Exercised, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Outstanding, end of period, aggregate intrinsic value Shares vested and expected to vest, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Exercisable at end of period, aggregate intrinsic value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Equity Method Investments Equity Method Investments Equity in loss of affiliate Cost method investments Cost Method Investments Fair Value Disclosures [Abstract] Reported Value Measurement [Member] Reported Value Measurement [Member] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Certificates of deposit Certificates of Deposit [Member] U.S. Government securities US Government Agencies Debt Securities [Member] U.S. Government sponsored entities US Government-sponsored Enterprises Debt Securities [Member] Municipal bonds US States and Political Subdivisions Debt Securities [Member] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Restricted cash Restricted Cash and Cash Equivalents, Fair Value Disclosure Restricted Cash and Cash Equivalents, Fair Value Disclosure Available-for-sale securities: Available-for-sale Securities Derivatives - asset position Foreign Currency Contract, Asset, Fair Value Disclosure Derivatives - liability position Foreign Currency Contracts, Liability, Fair Value Disclosure Contingent liability Business Combination, Contingent Consideration, Liability Assets (Liability), net Nature of business Nature of Operations [Text Block] Fiscal year Fiscal Period, Policy [Policy Text Block] Principles of consolidation Consolidation, Policy [Policy Text Block] Investments in affiliates Investment, Policy [Policy Text Block] Use of estimates Use of Estimates, Policy [Policy Text Block] Cash and cash equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Restricted cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Inventories Inventory, Policy [Policy Text Block] Allowance for doubtful accounts Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Revenue recognition Revenue Recognition, Policy [Policy Text Block] Revenue recognition - Long-term construction-type contracts Revenue Recognition, Long-term Contracts [Policy Text Block] Revenue recognition - Equipment contracts Revenue Recognition, Sales of Goods [Policy Text Block] Revenue recognition - Extended warranty and product maintenance Revenue Recognition, Deferred Revenue [Policy Text Block] Revenue recognition - Services Revenue Recognition, Sales of Services [Policy Text Block] Revenue recognition - Software Revenue Recognition, Software [Policy Text Block] Revenue recognition - Multiple-element arrangements Revenue Recognition, Multiple-deliverable Arrangements, Description [Policy Text Block] Revenue recognition - Long-term receivables and advertising rights Revenue Recognition, Long-term Receivables and Advertising Rights [Policy Text Block] Revenue Recognition, Long-term Receivables and Advertising Rights [Policy Text Block] Property and equipment Property, Plant and Equipment, Policy [Policy Text Block] Impairment of long-lived assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Goodwill and other intangible assets Goodwill and Intangible Assets, Policy [Policy Text Block] Software cost to be sold, leased, or marketed Software to be Sold, Leased, or Otherwise Marketed, Policy [Policy Text Block] Foreign currency translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Income taxes Income Tax, Policy [Policy Text Block] Comprehensive income Comprehensive Income, Policy [Policy Text Block] Product design and development Research and Development Expense, Policy [Policy Text Block] Advertising costs Advertising Costs, Policy [Policy Text Block] Shipping and handling cost Shipping and Handling Cost, Policy [Policy Text Block] Earnings per share (EPS) Earnings Per Share, Policy [Policy Text Block] Share-based compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Recent accounting pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Cash dividend declared (usd per share) Common Stock, Dividends, Per Share, Declared Schedule of Goodwill Schedule of Goodwill [Table Text Block] Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Table Text Block] Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Compensation Employee-related Liabilities, Current Taxes, other than income taxes Accrual for Taxes Other than Income Taxes, Current Accrued employee benefits Accrued Employee Benefits, Current Short-term accrued expenses Accrued Liabilities and Other Liabilities Claims liabilities Other Accrued Liabilities, Current Accrued expenses Accrued Liabilities, Current Statement of Financial Position [Abstract] ASSETS Assets [Abstract] CURRENT ASSETS: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value 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, Current Current maturities of long-term receivables Notes, Loans and Financing Receivable, Net, Current Prepaid expenses and other assets Prepaid Expense and Other Assets, Current Income tax receivables Income Taxes Receivable, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Long-term receivables, less current maturities Notes, Loans and Financing Receivable, Net, Noncurrent Goodwill Goodwill Intangibles, net Finite-Lived Intangible Assets and Indefinite-Lived Intangible Assets, Net Finite-Lived Intangible Assets and Indefinite-Lived Intangible Assets, Net Investment in affiliates and other assets Investments and Other Noncurrent Assets Deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Noncurrent TOTAL ASSETS Assets LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity [Abstract] CURRENT LIABILITIES: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued expenses Warranty obligations Product Warranty Accrual, Current Billings in excess of costs and estimated earnings Billings in Excess of Cost, Current Customer deposits Customer Deposits, Current Deferred revenue Deferred Revenue, Current Current portion of other long-term obligations Other Long-term Debt, Current Income taxes payable Accrued Income Taxes, Current Total current liabilities Liabilities, Current Long-term warranty obligations Product Warranty Accrual, Noncurrent Long-term deferred revenue Deferred Revenue, Noncurrent Other long-term obligations Other Liabilities, Noncurrent Long-term income tax payable Liability for Uncertainty in Income Taxes, Noncurrent Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Total long-term liabilities Liabilities, Noncurrent SHAREHOLDERS' EQUITY: Stockholders' Equity Attributable to Parent [Abstract] Common stock, no par value, authorized 120,000,000 shares; 44,779,534 and 44,372,357 shares issued at April 28, 2018 and April 29, 2017, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock, at cost, 303,957 and 303,957 shares at April 28, 2018 and April 29, 2017, respectively Treasury Stock, Value Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax TOTAL SHAREHOLDERS' EQUITY TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity Operating Loss Carryforwards [Table] Operating Loss Carryforwards [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] International Foreign Tax Authority [Member] Canada CANADA Ireland and Belgium [Domain] Ireland and Belgium [Domain] Ireland and Belgium [Domain] Operating Loss Carryforwards [Line Items] Operating Loss Carryforwards [Line Items] Operating loss carryforwards Operating Loss Carryforwards Deferred tax assets, gross Deferred Tax Assets, Gross Deferred tax asset valuation allowance Deferred Tax Assets, Valuation Allowance Accrued interest or penalties Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Commitments and Contingencies Disclosure [Abstract] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Out-of-Home Product Application [Member] Out-of-Home Product Application [Member] Out-of-Home Product Application [Member] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Performance guarantees Performance Guarantee [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Letter of credit and bank guarantees agreements Financial Standby Letter of Credit [Member] Surety bonds Surety Bond [Member] Minimum Minimum [Member] Maximum Maximum [Member] Guarantor Obligations Guarantor Obligations [Line Items] Guarantees: Guarantees [Abstract] Performance guarantees outstanding Loss Contingency Accrual Warranties: Product Warranties Disclosures [Abstract] Standard parts warranty period Product Warranty Accrual, Standard Parts Warranty Coverage Term Product Warranty Accrual, Standard Parts Warranty Coverage Term Installation warranty period Product Warranty Accrual, Installation Warranty Coverage Term Product Warranty Accrual, Installation Warranty Coverage Term Movement in Standard Product Warranty Accrual Movement in Standard Product Warranty Accrual [Roll Forward] Beginning accrued warranty costs Standard and Extended Product Warranty Accrual Warranties issued during the period Standard and Extended Product Warranty Accrual, Increase for Warranties Issued Settlements made during the period Standard and Extended Product Warranty Accrual, Decrease for Payments Ending accrued warranty costs Retirement Benefits [Abstract] Percentage of matching contribution Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay Maximum annual contribution percentage Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent Award requisite service period Defined Contribution Plan, Award Requisite Service Period Defined Contribution Plan, Award Requisite Service Period Minimum age attained for award Defined Contribution Plan, Attained Age Defined Contribution Plan, Attained Age Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Title of Individual [Axis] Title of Individual [Axis] Title of Individual with Relationship to Entity [Domain] Relationship to Entity [Domain] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] Contributions Defined Contribution Plan, Cost Supplemental Cash Flow Information [Abstract] Summary of Changes in Operating Assets and Liabilities Cash Flow, Operating Capital [Table Text Block] Schedule of Supplemental Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of Non-Cash Investing and Financing Activities Schedule of Other Significant Noncash Transactions [Table Text Block] Marketable Securities [Abstract] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Restricted Stock and Restricted Stock Units Restricted Stock and Restricted Stock Units [Member] Restricted Stock and Restricted Stock Units [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Number of Nonvested Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Outstanding at beginning of year, Nonvested Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted, Nonvested Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested, Nonvested Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited, Nonvested Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding at end of year, Nonvested Shares Weighted Average Grant Date Fair Value Per Share Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding at beginning of year, Weighted Average Grant Date Fair Value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted, Weighted Average Grant Date Fair Value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Vested, Weighted Average Grant Date Fair Value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited, Weighted Average Grant Date Fair Value (usd per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Outstanding at end of year, Weighted Average Grant Date Fair Value (usd per share) Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Fair value of options granted Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Expected dividend rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Expected life of option Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Commitments and Contingencies [Abstract] Commitments and Contingencies [Abstract] Other Commitments [Table] Other Commitments [Table] Other Commitments [Axis] Other Commitments [Axis] Other Commitments [Domain] Other Commitments [Domain] Advertising Advertising [Member] Advertising [Member] Deferred purchase price Deferred Purchase Price [Member] Deferred Purchase Price [Member] Long-term Debt [Member] Long-term Debt [Member] Other Commitments [Line Items] Other Commitments [Line Items] Other Commitment Other Commitment Less: current liability Other Commitment, Due in Next Twelve Months Other long-term obligations Other Commitments, Excluding Current Other Commitments, Excluding Current Discontinued Operations and Disposal Groups [Abstract] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Non-Digital Division [Member] Non-Digital Division [Member] Non-Digital Division [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Assets sold Disposal Group, Including Discontinued Operation, Assets Gain from sale of non-digital division Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Total cash, cash equivalents, and restricted cash shown in the statement of cash flows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Goodwill Goodwill [Roll Forward] Balance as of April 29, 2017: Foreign currency translation Goodwill, Foreign Currency Translation Gain (Loss) Balance as of April 28, 2018: Selected Financial Statement Data Additional Financial Information Disclosure [Text Block] Schedule of Fair Value Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Rollforward of Level 3 Contingent Consideration Liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Schedule of Pretax Income Domestic and Foreign Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block] Schedule of Components of Income Tax Expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Current and Non Current Schedule of Deferred Tax Assets and Liabilities Current and Non Current [Table Text Block] Schedule of Deferred Tax Assets and Liabilities Current and Non Current [Table Text Block] Reconciliation of Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Document Period End Date Document Period End Date Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Document Fiscal Year Focus Document Fiscal Period Focus Document Type Amendment Flag Schedule of Inventories Schedule of Inventory, Current [Table Text Block] Schedule of Property and Equipment Property, Plant and Equipment [Table Text Block] Schedule of Accrued Expenses Schedule of Accrued Liabilities [Table Text Block] Schedule of Other (Expense) Income Schedule of Other Nonoperating Income (Expense) [Table Text Block] Retirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Cost of goods sold Cost of Sales [Member] Selling Selling and Marketing Expense [Member] General and administrative General and Administrative Expense [Member] Product design and development Product Design and Development [Member] Product Design and Development [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Share-based compensation expense Allocated Share-based Compensation Expense Raw materials Inventory, Raw Materials, Net of Reserves Work-in-process Inventory, Work in Process, Net of Reserves Finished goods Inventory, Finished Goods, Net of Reserves Inventories Class of Stock Disclosures [Abstract] Class of Treasury Stock [Table] Class of Treasury Stock [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Equity, Class of Treasury Stock [Line Items] Equity, Class of Treasury Stock [Line Items] Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Stock Repurchased During Period, Shares Stock Repurchased During Period, Shares Stock Repurchased During Period, Value Stock Repurchased During Period, Value Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Segment Reporting Segment Reporting Disclosure [Text Block] Valuation and Qualifying Accounts [Abstract] SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Unasserted Claim [Member] Insurance Claims [Member] Collectibility of Receivables [Member] Collectibility of Receivables [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Loss Contingency, Estimate of Possible Loss Loss Contingency, Estimate of Possible Loss Loss contingency accrual Income Tax Holiday [Table] Income Tax Holiday [Table] Income Tax Holiday [Line Items] Income Tax Holiday [Line Items] Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Allowance for Doubtful Accounts Allowance for Doubtful Accounts [Member] Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Balance at Beginning of Year Valuation Allowances and Reserves, Balance Charged to Costs and Expenses Valuation Allowances and Reserves, Additions for Charges to Cost and Expense Charged to Other Accounts Valuation Allowances and Reserves, Additions for Charges to Other Accounts Deductions Valuation Allowances and Reserves, Deductions Balance at End of Year Capitalized software development costs for software sold to customers [Abstract] Capitalized software development costs for software sold to customers [Abstract] Capitalized Software Development Costs for Software Sold to Customers Capitalized Software Development Costs for Software Sold to Customers Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Restrictions on Cash and Cash Equivalents Restrictions on Cash and Cash Equivalents [Table Text Block] Schedule of Earnings Per Share Reconciliation Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Property, Plant and Equipment [Abstract] Depreciation Depreciation Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Contingent Consideration Liability [Member] Contingent Consideration Liability [Member] Contingent Consideration Liability [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Contingent liability as of April 29, 2017 Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Interest Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Foreign currency translation Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) Contingent liability as of April 28, 2018 Derivative Instruments and Hedging Activities Disclosure [Abstract] Schedule of Notional Amounts of Outstanding Derivative Positions Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Long-Lived Assets Goodwill and Intangible Assets Disclosure [Text Block] 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 Treasury stock, at cost (in shares) Treasury Stock, Shares Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities Schedule of Available-for-sale Securities [Line Items] Amortized Cost Available-for-sale Debt Securities, Amortized Cost Basis Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Fair Value Line of Credit Facility [Table] Line of Credit Facility [Table] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Line of Credit Line of Credit [Member] Standby Letters of Credit Standby Letters of Credit [Member] Foreign Line of Credit Foreign Line of Credit [Member] Bank guarantee Guarantees [Member] Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Debt instrument, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Line of credit facility, unused capacity, commitment fee percentage Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Line of Credit Facility, Amount Outstanding Long-term Line of Credit Debt instrument, restrictive covenants, fixed charge coverage ratio Debt Instrument, Restrictive Covenants, Fixed Charge Coverage Ratio Debt Instrument, Restrictive Covenants, Fixed Charge Coverage Ratio Debt instrument, restrictive covenants, capital expenditure reserve, amount Debt Instrument, Restrictive Covenants, Capital Expenditure Reserve, Amount Debt Instrument, Restrictive Covenants, Capital Expenditure Reserve, Amount Debt instrument, restrictive covenants, interest-bearing debt, ratio Debt Instrument, Restrictive Covenants, Interest-Bearing Debt, Ratio Debt Instrument, Restrictive Covenants, Interest-Bearing Debt, Ratio Supplemental Cash Flow Elements [Abstract] Cash payments for: Interest Interest Paid Income taxes, net of refunds Income Taxes Paid, Net Receivables [Abstract] Receivables Financing Receivables [Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Receivable Type [Axis] Receivable Type [Axis] Receivable Type [Domain] Receivable [Domain] Financing Receivable Financing Receivable [Member] Receivables Accounts, Notes, Loans and Financing Receivable [Line Items] Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Long-term contracts and lease receivables, present value Financing Receivable, Net Contract and lease receivables annual interest rates Loans and Leases Receivable, Interest Rate Loans and Leases Receivable, Interest Rate Long-term contracts and lease receivables, face amount Financing Receivable, Gross Retainage on construction-type contracts, expected to be collected in one year Contract Receivable Retainage, Next Twelve Months Less than 12 months Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value Greater than 12 months Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Total Available-for-sale Securities, Debt Securities Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract] 2019 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Finite-Lived Intangible Assets, Net Finite-Lived Intangible Assets, Net Income Statement [Abstract] Cost of sales Cost of Revenue Gross profit Operating expenses: Selling Selling Expense Total operating expenses Operating Expenses Operating income Income before income taxes Net income Weighted average shares outstanding: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Basic (in shares) Weighted Average Number of Shares Outstanding, Basic Diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Earnings per share: Earnings Per Share [Abstract] Basic (in dollars per share) Diluted (in dollars per share) Demonstration equipment transferred to inventory Demonstration equipment transferred to inventory Value of demonstration equipment transferred to inventory in noncash transaction during the reporting period. Purchases of property and equipment included in accounts payable Capital Expenditures Incurred but Not yet Paid Contributions of common stock under the employee stock purchase plan Stock Issued Contingent consideration related to acquisition of ADFLOW Supplemental Deferred Purchase Price Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block] Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Advertising expense Advertising Expense Schedule of Quarterly Financial Data Quarterly Financial Information [Table Text Block] Stock Options Employee Stock Option [Member] Employee Stock Employee Stock [Member] Share-based compensation Share-based Compensation Fair Value Measurement Fair Value Disclosures [Text Block] Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Deferred taxes assets: Components of Deferred Tax Assets [Abstract] Accrued warranty obligations Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Warranty Reserves Vacation accrual Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Compensated Absences Deferred maintenance revenue Deferred Tax Assets, Deferred Income Allowance for excess and obsolete inventory Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Other Equity compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Allowance for doubtful accounts Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts Inventory capitalization Deferred Tax Assets, Inventory Accrued compensation and benefits Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Other Unrealized loss on foreign currency exchange Deferred Tax Assets, Unrealized Currency Losses Net operating loss carry forwards Deferred Tax Assets, Operating Loss Carryforwards Research and development tax credit carry forwards Deferred Tax Assets, Tax Credit Carryforwards, Research Other Deferred Tax Assets, Other Deferred tax assets, gross Valuation allowance Deferred tax assets net of valuation Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Components of Deferred Tax Liabilities [Abstract] Property and equipment Deferred Tax Liabilities, Property, Plant and Equipment Prepaid expenses Deferred Tax Liabilities, Prepaid Expenses Intangible assets Deferred Tax Liabilities, Intangible Assets Other Deferred Tax Liabilities, Other Deferred tax liabilities, gross Deferred Tax Liabilities, Gross Deferred tax assets, net Deferred Tax Assets, Net Cash dividends declared per share Non-current assets Deferred Tax Assets, Net, Noncurrent Non-current liabilities Treasury Stock [Text Block] Treasury Stock [Text Block] Shareholders' Equity and Share-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] (Increase) decrease: Increase (Decrease) in Operating Assets [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Long-term receivables Increase (Decrease) in Long-term Receivables, Current Inventories Increase (Decrease) in Inventories Costs and estimated earnings in excess of billings Increase (Decrease) in Cost in Excess of Billing on Uncompleted Contract Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Income taxes receivable Increase (Decrease) in Income Taxes Receivable Investment in affiliates and other assets Increase (Decrease) in Other Operating Assets Increase (decrease): Increase (Decrease) in Operating Liabilities [Abstract] Current marketing obligations and other payables Increase (decrease) in Current marketing obligations and other payables Increase (decrease) in Current marketing obligations and other payables Accounts Payable Increase (Decrease) in Accounts Payable Customer deposits Increase (Decrease) in Customer Deposits Accrued expenses Increase (Decrease) in Accrued Liabilities Warranty obligations Increase (Decrease) In Short-Term Warranty Obligation Increase (Decrease) In Short-Term Warranty Obligation Billings in excess of costs and estimated earnings Increase (Decrease) in Billing in Excess of Cost of Earnings Long-term warranty obligations Increase (Decrease) In Long-Term Warranty Obligation Increase (Decrease) In Long-Term Warranty Obligation Income taxes payable Increase (Decrease) in Income Taxes Payable Deferred revenue Increase (Decrease) in Deferred Revenue Long-term marketing obligations and other payables Increase (Decrease) in Other Operating Liabilities Change in operating assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Schedule of Product Warranty Liability Schedule of Product Warranty Liability [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Long-term Purchase Commitment Long-term Purchase Commitment [Table Text Block] Other Long-term Obligations Other Commitments [Table Text Block] Schedule of Operating Leased Assets [Table] Schedule of Operating Leased Assets [Table] Leases, Purchase Price Option [Axis] Leases, Purchase Price Option [Axis] Leases, Purchase Price Option [Axis] Leases, Purchase Price Option [Domain] Leases, Purchase Price Option [Domain] Leases, Purchase Price Option [Domain] March 31, 2017 to March 31, 2022 March 31, 2017 to March 31, 2022 [Member] March 31, 2017 to March 31, 2022 [Member] Year ending March 2023 April 1, 2022 to March 31, 2023 [Member] April 1, 2022 to March 31, 2023 [Member] Year ending March 2024 April 1, 2023 to March 31, 2024 [Member] April 1, 2023 to March 31, 2024 [Member] Operating Leased Assets Operating Leased Assets [Line Items] Operating leases, purchase option price Operating Leases, Purchase Option Price Operating Leases, Purchase Option Price Operating leases, rent expense Operating Leases, Rent Expense, Net Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2019 Operating Leases, Future Minimum Payments, Remainder of Fiscal Year 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Land Land [Member] Buildings Building [Member] Machinery and equipment Machinery and Equipment [Member] Office furniture and equipment Furniture and Fixtures [Member] Computer software and hardware Computer Software and Hardware [Member] Computer Software and Hardware [Member] Equipment held for rental Equipment Held for Rental [Member] Equipment Held for Rental [Member] Demonstration equipment Demonstration Equipment [Member] Demonstration Equipment [Member] Transportation equipment Transportation Equipment [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property and equipment, gross Property, Plant and Equipment, Gross Less accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property and equipment, net Statement of Comprehensive Income [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Total other comprehensive income (loss), net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Costs and estimated earnings in excess of billings Billings in excess of costs and estimated earnings Costs in excess of billings, net Costs in Excess of Billings Office furniture and equipment Office Furniture and Equipment [Member] Office Furniture and Equipment [Member] Estimated useful life Property, Plant and Equipment, Useful Life Derivative [Table] Derivative [Table] Derivative, by Nature [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] U.S. Dollars/Australian Dollars USD to AUD [Member] USD to AUD [Member] U.S. Dollars/Canadian Dollars USD to CAD [Member] USD to CAD [Member] U.S. Dollars/British Pounds USD to GBP [Member] [Member] USD to GBP [Member] [Member] U.S. Dollars/Singapore Dollars USD to SGD [Member] USD to SGD [Member] U.S. Dollars/Euros USD to EUR [Member] USD to EUR [Member] U.S. Dollars/Swiss Franc USD to CHF [Member] [Member] USD to CHF [Member] [Domain] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Derivative Derivative [Line Items] Foreign Currency Exchange Forward Contracts: Derivative, Notional Amount Foreign currency contract, asset Foreign currency contract, liability Conditional purchase commitment Conditional Purchase Commitment, Amount Conditional Purchase Commitment, Amount Purchase Obligation, Fiscal Year Maturity Purchase Obligation, Fiscal Year Maturity [Abstract] 2019 Purchase Obligation, Due in Next Twelve Months 2020 Purchase Obligation, Due in Second Year 2021 Purchase Obligation, Due in Third Year 2022 Purchase Obligation, Due in Fourth Year 2023 Purchase Obligation, Due in Fifth Year Thereafter Purchase Obligation, Due after Fifth Year Total Purchase Obligation Undesignated Stock Undesignated Stock [Member] Undesignated Stock [Member] Independent Directors Director [Member] Restricted Stock Restricted Stock [Member] In The Money Options In The Money Options [Member] In The Money Options [Member] Shares authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Common purchase right per common stock Common Share Purchase Right Per Common Share, Ratio Common Share Purchase Right Per Common Share, Ratio Share price Share Price Days following ownership announcement option one Common Share Rights Exercise, Period, Option One Common Share Rights Exercise, Period, Option One Percentage of ownership Sale of Stock, Percentage of Ownership after Transaction Days following ownership announcement, option two Common Share Rights Exercise, Period, Option Two Common Share Rights Exercise, Period, Option Two Award life Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Shares available for grant Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Unrecognized compensation costs Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Weighted-average period for unrecognized costs Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Exercise price (usd per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Fair value of vested options Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Requisite service period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Employee maximum contribution percentage Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate Percentage of purchase price at the lower of the fair market value Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Offering Date Purchase discount percentage Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date Stock issued for ESPP Stock Issued During Period, Shares, Employee Stock Purchase Plans Shares reserved for future issuance Common Stock, Capital Shares Reserved for Future Issuance Nonvested unrecognized compensation expense Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Proceeds from exercise of stock options Proceeds from Stock Options Exercised Tax benefit from share based payments Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Schedule of Nonvested Restricted Stock and Restricted Stock Units Activity Schedule of Nonvested Restricted Stock and Restricted Stock Units Activity [Table Text Block] Schedule of Nonvested Restricted Stock and Restricted Stock Units Activity [Table Text Block] Schedule of Stock Option Award Activity Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Weighted-Average Assumptions Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of Share-Based Compensation Expense by Award Type Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of Share-Based Compensation Expense Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Summary of Uncompleted Contracts Schedule of Uncompleted Contracts [Table Text Block] Schedule of Uncompleted Contracts [Table Text Block] Costs in Excess of Billings Costs in Excess of Billings and Billings in Excess of Costs [Table Text Block] Unrecognized Tax Benefits that Would Impact Effective Tax Rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Reconciliation of Changes in Unrecognized Tax Benefits Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Unrecognized tax benefits, beginning balance Unrecognized Tax Benefits Gross increases related to prior period tax positions Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Gross increases related to current period tax positions Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Lapse of statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized tax benefits, ending balance Costs incurred Contract Receivable, Gross (Excluding Aggregate Billings), Costs Incurred Contract Receivable, Gross (Excluding Aggregate Billings), Costs Incurred Estimated earnings Contract Receivable, Gross (Excluding Aggregate Billings) Estimated Profit Contract Receivable, Gross (Excluding Aggregate Billings) Estimated Profit Costs and estimated earnings on uncompleted contracts Contract Receivable, Gross (Excluding Aggregate Billings) Contract Receivable, Gross (Excluding Aggregate Billings) Less billings to date Contract Receivable, Aggregate Billings Contract Receivable, Aggregate Billings Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Foreign Current Foreign Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Foreign Deferred Foreign Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Change in Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax for Accumulated Foreign Earnings, Provisional Income Tax Expense Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States UNITED STATES Outside United States Non-US [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Net sales: Geographic Areas, Revenues from External Customers [Abstract] Net sales Revenues Long-lived assets: Geographic Areas, Long-Lived Assets [Abstract] Long-lived assets Long-Lived Assets Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Table] Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Table] Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Trademarks Trademarks [Member] Computer Software, Intangible Asset [Member] Computer Software, Intangible Asset [Member] Customer Relationships [Member] Customer Relationships [Member] Other Other Assets [Member] Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Line Items] Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Line Items] [Line Items] for Schedule of Definite-Lived Intangible and Indefinite-Lived Intangible Assets [Table] Weighted Average Life (in years) Finite-Lived Intangible Asset, Useful Life Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Impairment Loss Finite-Lived Intangible Assets, Accumulated Impairment Loss Finite-Lived Intangible Assets, Accumulated Impairment Loss Definite-lived, Net Value Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] ADFLOW Networks [Member] ADFLOW Networks [Member] ADFLOW Networks [Member] Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] Percentage acquired Business Acquisition, Percentage of Voting Interests Acquired Business Combination, Contingent Consideration, Liability Deferred payments period Business Combination, Contingent Consideration, Deferred Payments Term Business Combination, Contingent Consideration, Deferred Payments Term Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Net income Net Income (Loss) Attributable to Parent [Abstract] Basic earnings per share Dilution associated with stock compensation plans Dilutive Securities, Effect on Basic Earnings Per Share, Options and Restrictive Stock Units Diluted earnings per share Net Income (Loss) Available to Common Stockholders, Diluted Shares Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Basic earnings per share (in shares) Dilution associated with stock compensation plans (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted earnings per share (in shares) Per share income (loss) Earnings Per Share Reconciliation [Abstract] Basic earnings per share (in dollars per share) Dilution associated with stock compensation plans (in dollars per share) Incremental Common Shares Attributable to Share-based Payment Arrangements, Per Share Amount Incremental Common Shares Attributable to Share-based Payment Arrangements, Per Share Amount Diluted earnings per share (in dollars per share) Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Antidilutive Securities Excluded from Computation of Earnings Per Share Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive securities excluded from computation of earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive securities excluded from computation of earnings per share, weighted average exercise price (in dollars per share) Antidilutive Securities Excluded from Computation of Earnings Per Share, Weighted Average Exercise Price Antidilutive Securities Excluded from Computation of Earnings Per Share, Weighted Average Exercise Price Domestic Income (Loss) from Continuing Operations before Income Taxes, Domestic Foreign Income (Loss) from Continuing Operations before Income Taxes, Foreign Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Business Combinations Business Combination Disclosure [Text Block] Statement of Cash Flows [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] CASH FLOWS FROM OPERATING ACTIVITIES: Net Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income 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 and amortization Depreciation, Amortization and Accretion, Net (Gain) loss on sale of property, equipment and other assets Gain (Loss) on Disposition of Property Plant Equipment Gain on sale of equity investment Equity Method Investment, Realized Gain (Loss) on Disposal Provision for doubtful accounts Provision for Doubtful Accounts Deferred income taxes, net Deferred Income Tax Expense (Benefit) Change in operating assets and liabilities 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 sales of property, equipment and other assets Proceeds from Sale of Property, Plant, and Equipment Purchases of marketable securities Payments to Acquire Marketable Securities Proceeds from sales or maturities of marketable securities Proceeds from Sale and Maturity of Marketable Securities Proceeds from sale of equity investment Proceeds from Sale of Equity Method Investments Purchases of equity investment Payments to Acquire Equity Method Investments Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired 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] Payments on notes payable Repayments of Notes Payable Principal payments on long-term obligations Repayments of Long-term Debt Dividends paid Payments of Ordinary Dividends, Common Stock Payments for common shares repurchased Payments for Repurchase of Common Stock Tax payments related to RSU issuances Payments Related to Tax Withholding for Share-based Compensation 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, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect CASH, CASH EQUIVALENTS AND RESTRICTED CASH: Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract] Beginning of period End of period Available-for-sale Securities Available-for-sale Securities [Table Text Block] Investments Classified by Contractual Maturity Date Investments Classified by Contractual Maturity Date [Table Text Block]