Industrial development revenue bonds Revolving credit facility borrowings, outstanding amount Long-term Debt Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Leases Lessee, Operating Leases [Text Block] Document Type Document Type Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Operating Lease Assets and Liabilities Lessee, Assets And Liabilities [Table Text Block] Lessee, Assets And Liabilities [Table Text Block] Activity in Product Warranty Accrual Schedule of Product Warranty Liability [Table Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Treasury Stock Treasury Stock [Member] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Cost of goods sold Cost of Goods and Services Sold Equity Components [Axis] Equity Components [Axis] Restricted Stock Restricted Stock [Member] 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 Deduction for warranty charges Standard and Extended Product Warranty Accrual, Decrease for Payments Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Debt Instrument, Name Debt Instrument, Name [Domain] Thereafter Lessee, Operating Lease, Liability, To Be Paid, After Year Four Lessee, Operating Lease, Liability, To Be Paid, After Year Four Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Minimum Minimum [Member] Guarantor Obligations, Nature Guarantor Obligations, Nature [Domain] Revenue from External Customer [Line Items] Revenue from External Customer [Line Items] Current operating lease liabilities Current operating lease liabilities Operating Lease, Liability, Current Lease accrual Operating Lease, Right-Of-Use Asset, Lease Accrual Operating Lease, Right-Of-Use Asset, Lease Accrual Range Statistical Measurement [Domain] LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Share Based Compensation Arrangement By Share Based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] 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 Accrued product warranty Balance at beginning of period Balance at end of period Product Warranty Accrual, Current Entity Interactive Data Current Entity Interactive Data Current United States UNITED STATES Security Exchange Name Security Exchange Name Fair Value Measurements Fair Value Disclosures [Text Block] Powell (UK) Limited Powell U K Limited [Member] Powell (UK) limited. Proceeds from life insurance policies Proceeds from Life Insurance Policy 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 Operating income (loss) Operating Income (Loss) Total Current Liabilities Liabilities, Current Additional paid-in capital Additional Paid in Capital, Common Stock Entity Registrant Name Entity Registrant Name Subsequent Event Type [Domain] Subsequent Event Type [Domain] Summary of Contract Asset and Liabilities Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Weighted average discount rate, percent Operating Lease, Weighted Average Discount Rate, Percent Assets: Assets, Fair Value Disclosure [Abstract] Transferred over Time Transferred over Time [Member] Outstanding at beginning of period (in dollars per share) Outstanding at end 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 Variable Rate Variable Rate [Domain] Variable Rate Variable Rate [Axis] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Commitments and Contingencies (Note F) Commitments and Contingencies Shares withheld in lieu of employee tax withholding Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Liabilities: Lease, Liabilities [Abstract] Lease, Liabilities [Abstract] Anniversary of Grant Date Share-based Payment Arrangement, Tranche Two [Member] ASSETS Assets [Abstract] Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Accounting Policies [Abstract] Accounting Policies [Abstract] Cash collateral pledged balance Line Of Credit Facility, Collateral Amount Line Of Credit Facility, Collateral Amount Stock-based compensation Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Entity Address, State or Province Entity Address, State or Province Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Accounts payable Accounts Payable, Current Less: sublease income Sublease Income Dividends paid Payments of Ordinary Dividends, Common Stock Interest rate Debt Instrument, Interest Rate, Effective Percentage Retained earnings Retained Earnings (Accumulated Deficit) Operating lease assets, net Operating lease assets, net Operating Lease, Right-of-Use Asset Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Accounts receivable, less allowance for credit losses of $382 and $510 Accounts Receivable, after Allowance for Credit Loss, Current Total future minimum lease payments Lessee, Operating Lease, Liability, to be Paid Shares issued, price per share (in shares) Shares Issued, Price Per Share Product Concentration Risk Product Concentration Risk [Member] 2022 Lessee, Operating Lease, Liability, to be Paid, Year One 2025 Lessee, Operating Lease, Liability, to be Paid, Year Four Fair Value of Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Total long-term debt Long-term Debt and Lease Obligation Entity Address, Postal Zip Code Entity Address, Postal Zip Code Canada CANADA Preferred stock, par value $0.01; 5,000,000 shares authorized; none issued Preferred Stock, Value, Issued Maturities of short-term investments Proceeds from Maturities, Prepayments and Calls of Short-term Investments Total lease cost Lease, Cost All others Other, Customers [Member] Other, Customers [Member] Document Transition Report Document Transition Report Raw materials, parts and sub-assemblies, net Inventory, Raw Materials and Supplies, Net of Reserves Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Other long-term liabilities Other Liabilities, Noncurrent Deferred income taxes Deferred Income Tax Assets, Net Numerator: Net Income (Loss) Attributable to Parent [Abstract] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Income taxes Increase (Decrease) in Income Taxes Payable Dividends per share (in dollars per share) Quarterly cash dividend (in dollars per share) Common Stock, Dividends, Per Share, Declared Borrowings Debt Instrument, Face Amount Debt covenant, consolidated interest coverage ratio (greater than) Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Effect of exchange rate changes on cash and cash equivalents Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Other current assets Other Assets, Current Document Quarterly Report Document Quarterly Report Liabilities: Liabilities, Fair Value Disclosure [Abstract] Inventories Total inventories Inventory, Net Vesting Vesting [Axis] Revenues Revenue from Contract with Customer, Excluding Assessed Tax Europe, Middle East and Africa EMEA [Member] Concentration risk, percentage Concentration Risk, Percentage Short-term investments Short-term Investments, Fair Value Disclosure Short-term Investments, Fair Value Disclosure Geographical [Domain] Geographical [Domain] Contract liabilities Contract liabilities Contract with Customer, Liability, Current Subsequent Event [Line Items] Subsequent Event [Line Items] Statement [Line Items] Statement [Line Items] Credit Facility Credit Facility [Domain] Diluted (in shares) Weighted average diluted shares (in shares) Weighted Average Number of Shares Outstanding, Diluted Class of Stock Class of Stock [Domain] Basic (in dollars per share) Earnings Per Share, Basic Earnings (loss) per share: Earnings Per Share, Basic and Diluted [Abstract] Entity File Number Entity File Number Forfeited/canceled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Debt Disclosure [Abstract] Debt Disclosure [Abstract] Weighted average remaining lease term Operating Lease, Weighted Average Remaining Lease Term Statement [Table] Statement [Table] Range Statistical Measurement [Axis] 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. Industrial Development Revenue Bonds Industrial Development Revenue Bonds [Member] Industrial development revenue bonds. Operating Activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Credit Facility Credit Facility [Axis] Common stock, par value $0.01; 30,000,000 shares authorized; 12,497,691 and 12,422,411 shares issued, respectively Common Stock, Value, Outstanding Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Payments on industrial development revenue bonds Repayments of Long-term Debt Remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Deferred compensation Deferred Compensation Liability, Current and Noncurrent Compensation expense Share-based Payment Arrangement, Expense Electric utility Electricity [Member] Retention amounts included in accounts receivable Contract with Customer, Receivable, after Allowance for Credit Loss Document Fiscal Year Focus Document Fiscal Year Focus Entity Small Business Entity Small Business Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Current maturities of long-term debt Long-term Debt, Current Maturities Entity Current Reporting Status Entity Current Reporting Status Fair Value Hierarchy Fair Value Hierarchy and NAV [Domain] Prepaid expenses Prepaid Expense, Current Goodwill and intangible assets, net Intangible Assets, Net (Including Goodwill) Amendment Flag Amendment Flag Subsequent Event [Table] Subsequent Event [Table] 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] Assets: Lease, Assets [Abstract] [Abstract] Lease, Assets [Abstract] [Abstract] Stock-based compensation (in shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Weighted average shares: Denominator: Weighted Average Number of Shares Outstanding, Diluted [Abstract] 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 Vesting, percentage Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Performance Based Restricted Stock Unit Performance Based Restricted Stock Unit [Member] Performance based restricted stock unit. Common stock, shares issued (in shares) Common Stock, Shares, Issued Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Revenue from External Customers by Products and Services [Table] Revenue from External Customers by Products and Services [Table] Other current liabilities Other Accrued Liabilities, Current Detail of Selected Balance Sheet Accounts Supplemental Balance Sheet Disclosures [Text Block] Total lease liabilities Present value of lease liabilities Operating Lease, Liability Net cash provided by (used in) operating activities Net Cash Provided by (Used in) Operating Activities Entity Central Index Key Entity Central Index Key Long-term debt, net of current maturities Long-term Debt, Excluding Current Maturities Accounts receivable, net Increase (Decrease) in Accounts Receivable Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Total Stockholders' Equity Balance Balance Stockholders' Equity Attributable to Parent Surety Bonds Surety Bond [Member] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Total Liabilities and Stockholders' Equity Liabilities and Equity Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Income Taxes Income Tax Disclosure [Text Block] Income taxes receivable Income Taxes Receivable, Current Entity Address, City or Town Entity Address, City or Town Geographical [Axis] Geographical [Axis] Accrued compensation and benefits Employee-related Liabilities, Current Subsequent Events Subsequent Events [Text Block] Fair Value, Hierarchy Fair Value Hierarchy and NAV [Axis] Restricted stock issued (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Restricted Stock Units (RSUs) Restricted Stock Units (RSUs) [Member] Operating lease cost Operating Lease, Cost Assets and Liabilities, Lessee [Abstract] Assets and Liabilities, Lessee [Abstract] Retained amount expected to be collected Contract with Customer, Receivable, after Allowance for Credit Loss, Noncurrent Line Of Credit Facility [Line Items] Line of Credit Facility [Line Items] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Short-term lease cost Short-term Lease, Cost Schedule of Restricted Stock Units Activity Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] Equity Component [Domain] Equity Component [Domain] 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. Allowance for doubtful accounts Balance at beginning of period Balance at end of period Accounts Receivable, Allowance for Credit Loss, Current Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Facility Agreement Facility Agreement [Member] Facility agreement. 2023 Lessee, Operating Lease, Liability, to be Paid, Year Two Gross profit Gross Profit Property, plant and equipment, net Property, Plant and Equipment, Net Selling, general and administrative expenses Selling, General and Administrative Expense Entity Tax Identification Number Entity Tax Identification Number Debt covenant, consolidated leverage ratio (less than) Debt Instrument, Covenant, Leverage Ratio, Maximum Allowed Debt Instrument, Covenant, Leverage Ratio, Maximum allowed Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Deferred compensation Deferred Compensation Liability, Classified, Noncurrent Amortization of intangible assets Amortization of Intangible Assets Stock-Based Compensation Share-based Payment Arrangement [Text Block] Net income (loss) Net income (loss) Net (loss) income Net Income (Loss) Attributable to Parent Lease Cost Lease, Cost [Table Text Block] Line Of Credit Facility [Table] Line of Credit Facility [Table] Changes in operating assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] 2024 Lessee, Operating Lease, Liability, to be Paid, Year Three Remainder of 2021 Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Other assets Other Assets, Noncurrent Plan Name Plan Name [Axis] LIBOR London Interbank Offered Rate (LIBOR) [Member] Work-in-progress Inventory, Work in Process, Gross Leases [Abstract] Leases [Abstract] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Overview and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Amended and Restated Credit Agreement Amended And Restated Credit Agreement [Member] Amended And Restated Credit Agreement [Member] Total Assets Assets Total Current Assets Assets, Current Current Fiscal Year End Date Current Fiscal Year End Date Revenue from Contract with Customer Benchmark Revenue from Contract with Customer Benchmark [Member] Time Based Restricted Stock Unit Time Based Restricted Stock Unit [Member] Time based restricted stock unit. Earnings (loss) per share: Earnings Per Share [Abstract] Change due to foreign currency translation Increase (Decrease) Due To Foreign Currency Translation Increase (decrease) due to foreign currency translation. Unvested restricted stock outstanding (in shares) Outstanding at beginning of period (in shares) Outstanding at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Title of 12(b) Security Title of 12(b) Security 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. Income taxes payable Accrued Income Taxes, Current Subsequent Event Type [Axis] Subsequent Event Type [Axis] Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Other assets Other Assets, Fair Value Disclosure RSU Activity (number of shares) [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Vesting Vesting [Domain] Document Fiscal Period Focus Document Fiscal Period Focus Interest expense Interest Expense Mexico, Central and South America Mexico, Central America And South America [Member] Mexico, Central America And South America [Member] Uncollectible accounts written off, net of recoveries Allowance For Doubtful Accounts Receivable Write Offs Recoveries Allowance for doubtful accounts receivable write offs (recoveries). Depreciation and amortization Depreciation, Depletion and Amortization Changes in contract estimates related to projects in progress Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Product and Service [Axis] Product and Service [Axis] Total Liabilities Liabilities Transferred at Point in Time Transferred at Point in Time [Member] Oil and gas Oil and Gas Service [Member] Less: present value discount (imputed interest) Lessee, Operating Lease, Liability, Undiscounted Excess Amount Financial Standby Letter of Credit Financial Standby Letter of Credit [Member] Entity Filer Category Entity Filer Category Common Stock Common Stock [Member] Product and Service [Domain] Product and Service [Domain] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Revenue recognized related to contract liabilities Contract with Customer, Liability, Revenue Recognized Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Increase to warranty expense Standard and Extended Product Warranty Accrual, Period Increase (Decrease) Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Inventories Increase (Decrease) in Inventories Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Accounts payable Increase (Decrease) in Accounts Payable 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] Other, net Increase (Decrease) in Other Operating Assets and Liabilities, Net Amount available under the credit facility Amount of credit facility remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Debt Instrument Debt Instrument [Axis] Additional Paid-in Capital Additional Paid-in Capital [Member] Cash collateral required for guarantees, period (greater than) Cash Collateral Required for Guarantees, Period Cash Collateral Required for Guarantees, Period Remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Bad debt expense (recovery), net Bad debt expense (recovery), net Accounts Receivable, Credit Loss Expense (Reversal) Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Accrued liabilities Increase (Decrease) in Accrued Liabilities Contract assets Contract assets Contract with Customer, Asset, after Allowance for Credit Loss, Current Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Balance (in shares) Balance (in shares) Common Stock, Shares, Outstanding Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Maturities of Operating Lease Liabilities Lessee, Operating Lease, Liability, Maturity [Table Text Block] Variable lease cost Variable Lease, Cost Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Additional bonding capacity Commitments And Contingencies Additional Bonding Capacity Commitments and contingencies additional bonding capacity. Retained amount expected to be collected in the next twelve months Contract with Customer, Receivable, after Allowance for Credit Loss, Current Basic (in shares) Weighted average basic shares (in shares) Weighted Average Number of Shares Outstanding, Basic Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Income (loss) before income taxes Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Research and development expenses Research and Development Expense Subsequent Events [Abstract] Subsequent Events [Abstract] Foreign currency translation adjustments Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Treasury stock, shares (in shares) Treasury Stock, Shares Subsequent Event Subsequent Event [Member] Common stock, shares authorized (in shares) Common Stock, Shares Authorized Concentration Risk Type [Axis] Concentration Risk Type [Axis] Plan Name Plan Name [Domain] Dilutive effect of restricted stock units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Less: current portion Long-term Debt and Lease Obligation, Current Revenue Revenue from Contract with Customer [Text Block] Net contract liability Contract With Customer, Asset (Liability), Net, Current Contract with Customer, Asset (Liability), Net, Current Guarantor Obligations, Nature Guarantor Obligations, Nature [Axis] Class of Stock Class of Stock [Axis] Income tax provision (benefit) Income tax provision (benefit) Income Tax Expense (Benefit) Income Statement [Abstract] Income Statement [Abstract] Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Accumulated Other Comprehensive Income/(Loss) AOCI Attributable to Parent [Member] Long-term operating lease liabilities Long-term operating lease liabilities Operating Lease, Liability, Noncurrent Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Diluted (in dollars per share) Earnings Per Share, Diluted Local Phone Number Local Phone Number U.S. Revolver Domestic Line of Credit [Member] Immediate Vesting Share-based Payment Arrangement, Tranche One [Member] Use of Estimates Use of Estimates, Policy [Policy Text Block] Current Assets: Assets, Current [Abstract] Interest income Investment Income, Interest Components of Long-term debt Schedule of Long-term Debt Instruments [Table Text Block] Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Entity Address, Address Line One Entity Address, Address Line One Entity Emerging Growth Company Entity Emerging Growth Company Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Deferred income taxes Deferred Income Tax Expense (Benefit) Petrochemical Petrochemical [Member] Petrochemical [Member] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Schedule of Calculation of the Effective Income Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Award Type Award Type [Axis] Weighted Average Grant 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] Legal Entity Legal Entity [Axis] Asia/Pacific Asia Pacific [Member] Purchases of property, plant and equipment, net Payments to Acquire Property, Plant, and Equipment City Area Code City Area Code Maximum Maximum [Member] Fed Funds Rate Fed Funds Effective Rate Overnight Index Swap Rate [Member] Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Document Period End Date Document Period End Date Long-Term Debt Long-term Debt [Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Dividends paid Dividends, Common Stock, Cash Purchases of short-term investments Payments to Acquire Short-term Investments Retained Earnings Retained Earnings [Member] Effective tax rate Effective Income Tax Rate Reconciliation, Percent 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] Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Letters of credit collateral amount, minimum outstanding Letter of Credit, Collateral Amount, Minimum outstanding Letter of Credit, Collateral Amount, Minimum outstanding Schedule Of Share Based Compensation Arrangements By Share Based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Equity Award Award Type [Domain] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Guarantee liability Guarantee liability Guarantor Obligations, Current Carrying Value Movement in Standard Product Warranty Accrual [Roll Forward] Movement in Standard Product Warranty Accrual [Roll Forward] Schedule Of Guarantee Obligations [Table] Schedule of Guarantor Obligations [Table] Activity in Allowance for Doubtful Accounts Receivable Financing Receivable, Allowance for Credit Loss [Table Text Block] Trading Symbol Trading Symbol Traction power Traction Power Customer [Member] Traction Power Customer [Member] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Components of Inventories Schedule of Inventory, Current [Table Text Block] Stock-based compensation Share-based Payment Arrangement, Noncash Expense Entity Entity [Domain] Non Employee Director Equity Incentive Plan Non Employee Director Equity Incentive Plan [Member] 2014 Non-Employee Director Equity Incentive Plan Member Treasury stock, 806,018 shares at cost Treasury Stock, Value Shares withheld in lieu of employee tax withholding Payment, Tax Withholding, Share-based Payment Arrangement Earnings Per Share Earnings Per Share [Text Block] Cover [Abstract] Cover [Abstract] Base Rate Base Rate [Member] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Current Liabilities: Liabilities, Current [Abstract] Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Entity Shell Company Entity Shell Company Guarantee Obligations [Line Items] Guarantor Obligations [Line Items] Change due to foreign currency translation Standard and Extended Product Warranty Accrual, Foreign Currency Translation Gain (Loss) New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Short-term investments Short-term Investments