Organization, Consolidation and Presentation of Financial Statements [Abstract] Detail of Selected Balance Sheet Accounts Supplemental Balance Sheet Disclosures [Text Block] Income Tax Disclosure [Abstract] Effective tax rate Effective Income Tax Rate Reconciliation, Percent Deferred tax assets, valuation allowance Deferred Tax Assets, Valuation Allowance Unrecognized tax benefits, decrease due to expiration of certain federal statutes of limitations and voluntary filings Decrease in Unrecognized Tax Benefits is Reasonably Possible Share-based Payment Arrangement [Abstract] Schedule of Restricted Stock Units Activity Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Leases [Abstract] Lease Cost Lease, Cost [Table Text Block] Operating Lease Assets and Liabilities Lessee, Assets And Liabilities [Table Text Block] Lessee, Assets And Liabilities [Table Text Block] Maturities of Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Raw materials, parts and sub-assemblies, net Inventory, Raw Materials and Supplies, Net of Reserves Work-in-progress Inventory, Work in Process, Gross Total inventories Inventory, Net Statement of Financial Position [Abstract] Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Treasury stock, shares (in shares) Treasury Stock, Shares Operating lease cost Operating Lease, Cost Less: sublease income Sublease Income Variable lease cost Variable Lease, Cost Short-term lease cost Short-term Lease, Cost Total lease cost Lease, Cost Fair Value Disclosures [Abstract] Fair Value of Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Accounting Policies [Abstract] Overview and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Debt Disclosure [Abstract] Industrial development revenue bonds Long-term Debt Less: current portion Long-term Debt and Lease Obligation, Current Total long-term debt Long-term Debt and Lease Obligation Document And Entity Information [Abstract] Document and entity information. Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Emerging Growth Company Entity Emerging Growth Company Entity Small Business Entity Small Business Entity Shell Company Entity Shell Company Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Remainder of 2020 Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year 2021 Lessee, Operating Lease, Liability, Payments, Due Year Two 2022 Lessee, Operating Lease, Liability, Payments, Due Year Three 2023 Lessee, Operating Lease, Liability, Payments, Due Year Four 2024 Lessee, Operating Lease, Liability, Payments, Due Year Five Thereafter Lessee, Operating Lease, Liability, Payments, Due after Year Five Total future minimum lease payments Lessee, Operating Lease, Liability, Payments, Due Less: present value discount (imputed interest) Lessee, Operating Lease, Liability, Undiscounted Excess Amount Present value of lease liabilities Operating Lease, Liability Activity in Allowance for Doubtful Accounts Receivable Financing Receivable, Allowance for Credit Loss [Table Text Block] Components of Inventories Schedule of Inventory, Current [Table Text Block] Activity in Product Warranty Accrual Schedule of Product Warranty Liability [Table Text Block] Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] United States UNITED STATES Canada CANADA Europe, Middle East and Africa EMEA [Member] Asia/Pacific Asia Pacific [Member] Mexico, Central and South America Mexico, Central America And South America [Member] Mexico, Central America And South America [Member] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Oil and gas Oil and Gas Service [Member] Petrochemical Petrochemical [Member] Petrochemical [Member] Electric utility Electricity [Member] Traction power Traction Power Customer [Member] Traction Power Customer [Member] All others Other, Customers [Member] Other, Customers [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenues Revenue from Contract with Customer, Excluding Assessed Tax Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] ASSETS Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Short-term investments Short-term Investments Accounts receivable, less allowance for doubtful accounts of $300 and $301 Accounts Receivable, after Allowance for Credit Loss, Current Contract assets Contract with Customer, Asset, Net, Current Inventories Income taxes receivable Income Taxes Receivable, Current Prepaid expenses Prepaid Expense, Current Other current assets Other Assets, Current Total Current Assets Assets, Current Property, plant and equipment, net Property, Plant and Equipment, Net Operating lease assets, net Operating Lease, Right-of-Use Asset Goodwill and intangible assets, net Intangible Assets, Net (Including Goodwill) Deferred income taxes Deferred Income Tax Assets, Net Other assets Other Assets, Noncurrent Total Assets Assets LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Current Liabilities: Liabilities, Current [Abstract] Current maturities of long-term debt Long-term Debt, Current Maturities Accounts payable Accounts Payable, Current Contract liabilities Contract with Customer, Liability, Current Accrued compensation and benefits Employee-related Liabilities, Current Accrued product warranty Product Warranty Accrual, Current Current operating lease liabilities Operating Lease, Liability, Current Income taxes payable Accrued Income Taxes, Current Other current liabilities Other Accrued Liabilities, Current Total Current Liabilities Liabilities, Current Long-term debt, net of current maturities Long-term Debt, Excluding Current Maturities Deferred compensation Deferred Compensation Liability, Classified, Noncurrent Long-term operating lease liabilities Operating Lease, Liability, Noncurrent Other long-term liabilities Other Liabilities, Noncurrent Total Liabilities Liabilities Commitments and Contingencies (Note F) Commitments and Contingencies Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Preferred stock, par value $.01; 5,000,000 shares authorized; none issued Preferred Stock, Value, Issued Common stock, par value $.01; 30,000,000 shares authorized; 12,420,031 and 12,372,766 shares issued, respectively Common Stock, Value, Outstanding Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Treasury stock, 806,018 shares at cost Treasury Stock, Value Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total Stockholders' Equity Stockholders' Equity Attributable to Parent Total Liabilities and Stockholders' Equity Liabilities and Equity Movement in Standard Product Warranty Accrual [Roll Forward] Movement in Standard Product Warranty Accrual [Roll Forward] Balance at beginning of period Increase in warranty expense Standard and Extended Product Warranty Accrual, Period Increase (Decrease) Deduction for warranty charges Standard and Extended Product Warranty Accrual, Decrease for Payments Change due to foreign currency translation Standard and Extended Product Warranty Accrual, Foreign Currency Translation Gain (Loss) Balance at end of period Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Income Statement [Abstract] Cost of goods sold Cost of Goods and Services Sold Gross profit Gross Profit Selling, general and administrative expenses Selling, General and Administrative Expense Research and development expenses Research and Development Expense Amortization of intangible assets Amortization of Intangible Assets Operating income (loss) Operating Income (Loss) Interest expense Interest Expense Interest income Investment Income, Interest Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax provision Income Tax Expense (Benefit) Net income (loss) Net Income (Loss) Attributable to Parent Earnings (loss) per share: Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Weighted average shares: 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 Dividends per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Subsequent Events [Abstract] 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] Quarterly cash dividend (in dollars per share) Severance and restructuring costs (less than) Restructuring Costs Remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Statement of Comprehensive Income [Abstract] Net income (loss) Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Lease accrual Operating Lease, Right-Of-Use Asset, Lease Accrual Operating Lease, Right-Of-Use Asset, Lease Accrual Weighted average discount rate, percent Operating Lease, Weighted Average Discount Rate, Percent Weighted average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Line Of Credit Facility [Table] Line of Credit Facility [Table] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] U.S. Revolver Domestic Line of Credit [Member] Industrial Development Revenue Bonds Industrial Development Revenue Bonds [Member] Industrial development revenue bonds. Debt Instrument Debt Instrument [Axis] Debt Instrument, Name Debt Instrument, Name [Domain] Amended and Restated Credit Agreement Amended And Restated Credit Agreement [Member] Amended And Restated Credit Agreement [Member] Guarantor Obligations, Nature Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature Guarantor Obligations, Nature [Domain] Financial Standby Letter of Credit Financial Standby Letter of Credit [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Fed Funds Rate Fed Funds Effective Rate Overnight Index Swap Rate [Member] LIBOR London Interbank Offered Rate (LIBOR) [Member] Base Rate Base Rate [Member] Range Statistical Measurement [Axis] Range Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Line Of Credit Facility [Line Items] Line of Credit Facility [Line Items] Revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Revolving credit facility borrowings, outstanding amount Guarantee liability Guarantor Obligations, Current Carrying Value Amount available under the credit facility Line of Credit Facility, Remaining Borrowing Capacity Debt covenant, consolidated leverage ratio (less than) Debt Instrument, Covenant, Leverage Ratio, Maximum Allowed Debt Instrument, Covenant, Leverage Ratio, Maximum allowed Debt covenant, consolidated interest coverage ratio (greater than) Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Cash collateral pledged balance Line Of Credit Facility, Collateral Amount Line Of Credit Facility, Collateral Amount Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Percentage of voting capital stock pledged as collateral Percentage Of Domestic Capital Stock Pledged As Collateral For Credit Facility Percentage of domestic capital stock pledged as collateral for credit facility. Non-domestic subsidiaries of voting capital stock Percentage Of Non Domestic Capital Stock Pledged As Collateral For Credit Facility Percentage of non domestic capital stock pledged as collateral for credit facility. Borrowings Debt Instrument, Face Amount Reimbursement agreement requires annual redemptions Debt Instrument, Annual Principal Payment Interest rate Debt Instrument, Interest Rate, Effective Percentage Assets and Liabilities, Lessee [Abstract] Assets: Lease, Assets [Abstract] [Abstract] Lease, Assets [Abstract] [Abstract] Operating lease assets, net Liabilities: Lease, Liabilities [Abstract] Lease, Liabilities [Abstract] Current operating lease liabilities Long-term operating lease liabilities Total lease liabilities Contract assets Contract liabilities Net contract asset (liability) Contract With Customer, Asset (Liability), Net, Current Contract with Customer, Asset (Liability), Net, Current Revenue recognized related to contract liabilities Contract with Customer, Liability, Revenue Recognized Retention amounts included in accounts receivable Contract with Customer, Receivable, After Allowance For Credit Loss Contract with Customer, Receivable, after Allowance for Credit Loss Retained amount expected to be collected in the next twelve months Contract With Customer, Receivable, After Allowance For Credit Loss, Current Contract With Customer, Receivable, After Allowance For Credit Loss, Current Retained amount expected to be collected Contract With Customer, Receivable, After Allowance for Credit Loss, Noncurrent Contract With Customer, Receivable, After Allowance for Credit Loss, Noncurrent Summary of Contract Asset and Liabilities Contract with Customer, Asset and Liability [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Long-Term Debt Long-term Debt [Text Block] Revenue Revenue from Contract with Customer [Text Block] Income (loss) before income taxes Income tax provision Subsequent Events Subsequent Events [Text Block] Numerator: Net Income (Loss) Attributable to Parent [Abstract] Denominator: Weighted average basic shares (in shares) Dilutive effect of restricted stock units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average diluted shares (in shares) Income (loss) per share: Earnings Per Share, Basic and Diluted [Abstract] Components of Long-term debt Schedule of Long-term Debt Instruments [Table Text Block] Leases Lessee, Operating Leases [Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type Award Type [Axis] Equity Award Award Type [Domain] Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Restricted Stock Restricted Stock [Member] Class of Stock Class of Stock [Axis] Class of Stock Class of Stock [Domain] Time Based Restricted Stock Unit Time Based Restricted Stock Unit [Member] Time based restricted stock unit. Performance Based Restricted Stock Unit Performance Based Restricted Stock Unit [Member] Performance based restricted stock unit. Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] Non Employee Director Equity Incentive Plan Non Employee Director Equity Incentive Plan [Member] 2014 Non-Employee Director Equity Incentive Plan Member Vesting Vesting [Axis] Vesting Vesting [Domain] Immediate Vesting Share-based Payment Arrangement, Tranche One [Member] Anniversary of Grant Date Share-based Payment Arrangement, Tranche Two [Member] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Unvested restricted stock outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Compensation expense Share-based Payment Arrangement, Expense Shares issued under the plan (in shares) Share Based Compensation Arrangement By Share Based Payment Award Annual Shares Issuable Share-based compensation arrangement by share-based payment award annual shares issuable. Vesting, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Restricted stock issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Shares issued, price per share (in shares) Shares Issued, Price Per Share Reconciliation of Basic and Diluted Weighted Average Shares used in Computation of Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Income Taxes Income Tax Disclosure [Text Block] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] ASU 2016-02 Accounting Standards Update 2016-02 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Operating lease liabilities Stock-Based Compensation Share-based Payment Arrangement [Text Block] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Balance at beginning of period Bad debt expense Accounts Receivable, Credit Loss Expense (Reversal) Uncollectible accounts written off, net of recoveries Allowance For Doubtful Accounts Receivable Write Offs Recoveries Allowance for doubtful accounts receivable write offs (recoveries). Change due to foreign currency translation Increase (Decrease) Due To Foreign Currency Translation Increase (decrease) due to foreign currency translation. Balance at end of period Statement of Cash Flows [Abstract] Operating Activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock-based compensation Share-based Payment Arrangement, Noncash Expense Bad debt expense Deferred income taxes Deferred Income Tax Expense (Benefit) Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable, net Increase (Decrease) in Accounts Receivable Contract assets and liabilities, net Increase (Decrease) In Contract With Customer Asset And Liability, Net Increase (Decrease) In Contract With Customer Asset And Liability, Net Inventories Increase (Decrease) in Inventories Income taxes Increase (Decrease) in Income Taxes Payable Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Purchases of short-term investments Payments to Acquire Short-term Investments Maturities of short-term investments Proceeds from Maturities, Prepayments and Calls of Short-term Investments Purchases of property, plant and equipment, net Payments to Acquire Property, Plant, and Equipment Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Payments on industrial development revenue bonds Repayments of Long-term Debt Shares withheld in lieu of employee tax withholding Payment, Tax Withholding, Share-based Payment Arrangement Dividends paid Payments of Ordinary Dividends, Common Stock Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Effect of exchange rate changes on cash, cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period Schedule of Calculation of the Effective Income Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Revenue from External Customers by Products and Services [Table] Revenue from External Customers by Products and Services [Table] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Transferred over Time Transferred over Time [Member] Transferred at Point in Time Transferred at Point in Time [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Product Concentration Risk Product Concentration Risk [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue from Contract with Customer Benchmark Revenue from Contract with Customer Benchmark [Member] Revenue from External Customer [Line Items] Revenue from External Customer [Line Items] Concentration risk, percentage Concentration Risk, Percentage Changes in contract estimates related to projects in progress Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress 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 Income/(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 (in shares) Common Stock, Shares, Outstanding Balance Net income Foreign currency translation adjustments Stock-based compensation (in shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Stock-based compensation Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Shares withheld in lieu of employee tax withholding Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Issuance of restricted stock (in shares) Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Issuance of restricted stock Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Dividends paid Dividends, Common Stock, Cash Balance (in shares) Balance RSU Activity (number of shares) [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Number of Restricted Stock Units Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Outstanding at beginning of period (in shares) Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited/canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding at end of period (in shares) Weighted Average 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 period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (in dollars 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 (in dollars 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/canceled (in dollars 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 period (in dollars per share) Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Hierarchy Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy Fair Value Hierarchy and NAV [Domain] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Assets: Assets, Fair Value Disclosure [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Short-term investments Short-term Investments, Fair Value Disclosure Short-term Investments, Fair Value Disclosure Other assets Other Assets, Fair Value Disclosure Liabilities: Liabilities, Fair Value Disclosure [Abstract] Deferred compensation Deferred Compensation Liability, Current and Noncurrent Schedule Of Guarantee Obligations [Table] Schedule of Guarantor Obligations [Table] Surety Bonds Surety Bond [Member] Facility Agreement Facility Agreement [Member] Facility agreement. Legal Entity Legal Entity [Axis] Entity Entity [Domain] Powell (UK) Limited Powell U K Limited [Member] Powell (UK) limited. Guarantee Obligations [Line Items] Guarantor Obligations [Line Items] Additional bonding capacity Commitments And Contingencies Additional Bonding Capacity Commitments and contingencies additional bonding capacity. Amount of credit facility remaining borrowing capacity