Statement of Financial Position [Abstract] Cash and cash equivalents Cash and cash equivalents at beginning of year Cash and cash equivalents at end of year Marketable securities Accounts receivable, net of allowance for doubtful accounts of $189 in 2015 and $234 in 2014 Allowance for doubtful accounts (in Dollars) Costs and estimated earnings in excess of billings, net Net asset Inventories, net Inventory, Net Deferred and prepaid income taxes Prepaid expenses and other Total current assets Property, plant and equipment, at cost, net of accumulated depreciation and amortization Deferred income taxes Net noncurrent deferred tax assets Goodwill and other intangible assets Cash surrender value of life insurance and cash held in trust Other assets Total assets Identifiable Assets Accounts payable - trade Accrued liabilities Total current liabilities Long-term debt - noncurrent Deferred compensation Deferred rent and other liabilities Total liabilities Commitments and contingencies Preferred stock, $1.00 par value authorized 600 shares, no shares issued Preferred stock, par value (in Dollars per share) Preferred stock, shares authorized Preferred stock, shares issued Common stock, $1.00 par value; authorized 20,000 shares, 9,164 shares issued and 8,699 outstanding in 2015; 8,571 outstanding in 2014 Common stock, par value (in Dollars per share) Common stock, shares authorized Common stock shares issued Common stock, shares outstanding Balance (in Shares) Balance (in Shares) Additional paid-in capital Retained earnings Common stock reacquired and held in treasury - at cost (465 shares in 2015 and 593 shares in 2014) Treasury stock, shares Accumulated other comprehensive income Balance, Total Balance, Total Total stockholders' equity Balance Balance Total liabilities and stockholders' equity Income Statement [Abstract] Revenues Revenues Cost of revenues Gross margin Selling and administrative expenses Research and development expenses Operating profit Operating profit (loss) Investment income Interest expense Other (expense) income, net Income before provision for income taxes Provision for income taxes Total provision Net income Net Income Net income Basic (in Dollars per share) Diluted (in Dollars per share) Basic (in Shares) Basic EPS Shares outstanding (weighted average) Diluted (in Shares) Diluted EPS Shares outstanding Foreign currency translation adjustment Change in market value of marketable securities before reclassification, net of tax of ($176) and $130 Items of other comprehensive income (loss)before reclassification, net of taxes, Market Value of Marketable Securities Reclassification adjustment for realized gains included in net income, net of tax of $192 and $125 Tax effect - Change in Market Value of Marketable Securities Tax effect - Total Total unrealized loss on marketable securities, net of tax Total other comprehensive (loss) income Total other comprehensive income (loss), net of taxes, Total Comprehensive income Statement of Cash Flows [Abstract] Deferred income tax benefit Depreciation and amortization Deferred lease obligation Provision for losses on accounts receivable, inventories and warranty reserve Gains on marketable securities Loss (gain) on sale of fixed and other assets, net Employee benefit plans expense Employee Benefits and Share-based Compensation (in Dollars) Stock-based compensation expense Share-based Compensation (in Dollars) Tax benefit from exercise of stock-based compensation Accounts receivable Costs and estimated earnings in excess of billings Inventories Prepaid expenses and other Other assets Accounts payable - trade Accrued liabilities Income taxes refundable/payable Other liabilities Net cash provided by operating activities Purchase of marketable securities Proceeds from sale or redemption of marketable securities Capital expenditures Net cash provided by (used in) investing activities Proceeds from credit line borrowing Proceeds from Lines of Credit (in Dollars) Payment of short-term credit and lease obligations Tax benefit from exercise of stock-based compensation Net cash (used in) provided by financing activities Net (decrease) increase in cash and cash equivalents before effect of exchange rate changes Effect of exchange rate changes on cash and cash equivalents Net (decrease) increase in cash and cash equivalents Interest Income taxes Statement of Stockholders' Equity [Abstract] Contribution of stock to 401(k) plan Stock Issued During Period, Value, Employee Benefit Plan (in Dollars) Contribution of stock to 401(k) plan (in Shares) Stock Issued During Period, Shares, Employee Benefit Plan Stock-based compensation expense Stock-based compensation expense (in Shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Tax benefit from stock option exercise Exercise of stock options and stock appreciation rights - net of Exercise of stock options and stock appreciation rights - net of (in Shares) Options, Shares Exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Change in unrealized gains and losses on marketable securities, net of taxes Equity Components [Axis] Common Stock [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Treasury Stock [Member] AOCI Attributable to Parent [Member] Supplemental Cash Flow Elements [Abstract] Accounting Policies [Abstract] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Abstract] Risk-free interest rate Range [Axis] Minimum [Member] Maximum [Member] Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted [Abstract] Effect of Dilutive Securities Contractors [Abstract] 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 Inventory Disclosure [Abstract] Schedule of Inventory, Current [Abstract] Raw Materials and Component Parts Work in Progress Finished Goods Property, Plant and Equipment [Abstract] Schedule of Property, Plant and Equipment [Abstract] Buildings and building improvements Machinery, equipment and furniture Less, accumulated depreciation Schedule of Future Minimum Rental Payments for Operating Leases [Abstract] 2016 2017 2018 2019 Total future minimum lease payments Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Abstract] Eligible Item or Group for Fair Value Option [Axis] Fixed Income Securities [Member] Cost Gross Unrealized Gains Gross Unrealized Losses Fair Market Value Current Equity Securities [Member] Schedule of Unrealized Gain (Loss) on Investments [Abstract] Fair Value, Less than 12 months Unrealized Losses, Less than 12 months Fair Value, Morethan 12 months Unrealized Losses, More than 12 months Fair Value Unrealized Losses Schedule of Realized Gain (Loss) on Investments [Abstract] Schedule of Fair Value, by Balance Sheet Grouping [Abstract] Due after one year through five years Due after five years through ten years Major Types of Debt and Equity Securities [Axis] Debt Disclosure [Abstract] Payables and Accruals [Abstract] Schedule of Accrued Liabilities [Abstract] Vacation and other compensation Incentive compensation Payroll taxes Deferred revenue Warranty reserve Balance at beginning of year Balance at end of year Cost conversion Commissions Other Investment Holdings [Abstract]