Statement of Financial Position [Abstract] Cash and cash equivalents Cash and cash equivalents of continuing operations at end of year Marketable securities Accounts receivable, net of allowance for doubtful accounts of $187 in 2017 and $189 in 2016 Allowance for doubtful accounts (in Dollars) Costs and estimated earnings in excess of billings, net Net asset Inventories, net Inventory, Net Prepaid income taxes Prepaid expenses and other Current assets of discontinued operations Total current assets of discontinued operations Total current assets Property, plant and equipment, at cost, net of accumulated depreciation and amortization Deferred income taxes Goodwill and other intangible assets Cash surrender value of life insurance Other assets Non-current assets of discontinued operations Total non-current assets of discontinued operations Total assets Identifiable Assets Accounts payable - trade Accrued liabilities Current liabilities of discontinued operations Total current liabilities of discontinued operations Total current liabilities Long-term debt - noncurrent Deferred compensation Deferred rent and other liabilities Non-current liabilities of discontinued operations Total non-current liabilities of discontinued operations 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 8,817 outstanding in 2017; 8,753 outstanding in 2016 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 (347 shares in 2017 and 411 shares in 2016) Treasury stock, shares Accumulated other comprehensive income 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 (loss) profit Operating profit (loss) Investment income Interest expense Other income (expense), net (Loss) Income before provision for income taxes (Benefit) Provision for income taxes Total provision Net (loss) income from continuing operations Income (loss) from discontinued operations, net of tax Net income (loss) from discontinued operations Net income (loss) Net (loss) income Net (loss) income Net Income (Loss) Basic (loss) earnings from continued operations (in Dollars per share) Basic earnings (loss) from discontinued operations (in Dollars per share) Basic (loss) earnings per share (in Dollars per share) Diluted (loss) earnings from continued operations (in Dollars per share) Diluted earnings (loss) from discontinued operations (in Dollars per share) Diluted (loss) earnings per share (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 ($182) and $51, respectively 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 ($25) and $57, respectively Tax effect - Change in Market Value of Marketable Securities Tax effect - Total Total unrealized gain (loss) on marketable securities, net of tax Total other comprehensive income (loss), net of taxes, Marketable Securities Total other comprehensive income (loss) Total other comprehensive income (loss), net of taxes, Total Comprehensive (loss) income Statement of Cash Flows [Abstract] Deferred income tax benefit Depreciation and amortization Deferred lease obligation and other liabilities Provision for losses on accounts receivable, inventories and warranty reserve Losses (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 effect (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 (payable) refundable Other liabilities Cash provided by operating activities – continuing operations Cash provided by operating activities – discontinued operations Net cash provided by operating activities Purchase of marketable securities Proceeds from sale or redemption of marketable securities Capital expenditures Cash used in investing activities – continuing operations Cash used in investing activities – discontinued operations Net cash (used in) investing activities Proceeds from credit line borrowing Tax (effect) benefit from exercise of stock-based compensation Cash used in financing activities – continuing operations Cash used in financing activities – discontinued operations Net cash (used in) provided by financing activities Net decrease in cash and cash equivalents before effect of exchange rate changes Effect of exchange rate changes on cash and cash equivalents Net decrease in cash and cash equivalents Cash and cash equivalents at beginning of year Cash and equivalents at end of year Less cash and equivalents of discontinued operations at end of year 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] Accounting Policies [Abstract] Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Abstract] Range [Axis] Minimum [Member] Maximum [Member] Discontinued Operations and Disposal Groups [Abstract] Disposal Group Name [Axis] Consolidated Statements of Operations and Comprehensive (Loss) Income [Member] Disposal Groups, Including Discontinued Operations [Abstract] Balance Sheets [Member] Earnings Per Share [Abstract] Schedule of Earnings Per Share, Basic and Diluted [Abstract] Effect of Dilutive Securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [ [Abstract] 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] 2018 2019 2020 2021 2022 Thereafter Total future minimum lease payments Operating Leases, Future Minimum Payments Due Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-sale Securities [Abstract] Major Types of Debt and Equity Securities [Axis] Fixed Income Securities [Member] Cost Gross Unrealized Gains Gross Unrealized Losses Fair Market Value Equity Securities [Member] Schedule of Unrealized Gain (Loss) on Investments [Abstract]