Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Intangible Assets Subject to Amortization Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Estimated Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Debt Disclosure [Abstract] Components of Long-Term Debt Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Maturities of Long-Term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Commitments and Contingencies Disclosure [Abstract] Schedule of Future Minimum Annual Rental Commitments Under Leases Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Lease Expense and Sublease Income Schedule of Lease Expense and Sublease Income [Table Text Block] Schedule of Lease Expense and Sublease Income [Table Text Block] 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] Organization, Consolidation and Presentation of Financial Statements [Abstract] Activity in Allowance for Doubtful Accounts Financing Receivable, Allowance for Credit Loss [Table Text Block] Components of Inventories Schedule of Inventory, Current [Table Text Block] Schedule of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Activity in Warranty Accrual Schedule of Product Warranty Liability [Table Text Block] Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type Property, Plant and Equipment, Type [Domain] Land Land [Member] Buildings and improvements Building and Building Improvements [Member] Machinery and equipment Machinery and Equipment [Member] Furniture and fixtures Furniture and Fixtures [Member] Construction in process Construction in Progress [Member] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, plant and equipment gross Property, Plant and Equipment, Gross Less: Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Total property, plant and equipment, net Property, Plant and Equipment, Net Asset lives Property, Plant and Equipment, Useful Life Assets under capital leases Assets Held under Capital Leases [Member] Depreciation Depreciation Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Balance at beginning of period Accounts Receivable, Allowance for Credit Loss, Current 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 Financial Position [Abstract] 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 Restricted cash Restricted Cash and Cash Equivalents, Current Accounts receivable, less allowance for doubtful accounts of $301 and $157 Accounts Receivable, after Allowance for Credit Loss, Current Contract assets Contract with Customer, Asset, Net, Current Inventories Inventory, Net 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 Restricted cash Restricted Cash and Cash Equivalents, Noncurrent Goodwill and intangible assets, net Intangible Assets, Net (Including Goodwill) Other assets Deferred Income Tax Assets, Net Deferred income taxes 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 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 (Note J) Deferred Compensation Liability, Classified, Noncurrent Other long-term liabilities Other Liabilities, Noncurrent Total Liabilities Liabilities Commitments and Contingencies (Note H) 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; 12,372,766 and 12,280,556 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 Quarterly Financial Information Disclosure [Abstract] Quarterly Information Quarterly Financial Information [Text Block] Share-based Payment Arrangement [Abstract] 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] Common Stock Common Stock [Member] Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] 2014 Equity Incentive Plan Two Thousand Fourteen Equity Incentive Plan [Member] Two thousand fourteen equity incentive plan. 2014 Non-Employee Director Equity Incentive Plan Non Employee Director Equity Incentive Plan [Member] 2014 Non-Employee Director Equity Incentive Plan 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. Vesting Vesting [Axis] Vesting Vesting [Domain] Vesting of First Anniversary Share-based Payment Arrangement, Tranche One [Member] Vesting of Second Anniversary 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 Actual amount of RSUs earned based on cumulative earnings Share Based Compensation Arrangement By Share Based Payment Award Percent Of Actual Amount Of Units Earned Share based compensation arrangement by share based payment award percent of actual amount of units earned. Target RSUs granted range Share Based Compensation Arrangement By Share Based Payment Award Target R S U Granted Range Share based compensation arrangement by share based payment award target RSU granted range. Unvested restricted stock outstanding (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Common stock, capital shares reserved for future issuance (in shares) Common Stock, Capital Shares Reserved for Future Issuance Number of shares available for grant (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Maximum number of shares granted to any individual (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Maximum Number of Shares Per Employee Number of shares issued to any individual (in shares) Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Available For Grant Other Than Options And SARs Share based compensation arrangement by share based payment award number of shares available for grant other than options and SARs. Restricted stock issuable to eligible Board of Directors members annually (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 Shares issued under the plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Shares issued, price per share (in dollars per share) Shares Issued, Price Per Share Compensation expense Share-based Payment Arrangement, Expense Amounts not yet recognized related to non-vested stock totaled Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount Weighted average remaining contractual life Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition 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. 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] 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] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Federal Funds Rate Fed Funds Effective Rate Overnight Index Swap Rate [Member] Eurocurrency Rate Eurodollar [Member] London Interbank Offered Rate (LIBOR) [Member] London Interbank Offered Rate (LIBOR) [Member] Base Rate Base Rate [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 Long-term Debt Guarantee liability Guarantor Obligations, Current Carrying Value Amount of credit facility remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Revolving credit facility, increase (up to) Line of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option Line of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option Revolving credit facility, minimum of (or less) Line of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option, Incremental Borrowing Amount Line of Credit Facility, Accordion Feature, Higher Borrowing Capacity Option, Incremental Borrowing Amount Debt covenant, consolidated leverage ratio (greater than) Debt Instrument, Covenant, Leverage Ratio, Maximum Allowed Debt Instrument, Covenant, Leverage Ratio, Maximum allowed Debt covenant, consolidated interest coverage ratio (less 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 Restricted cash Restricted Cash and Cash Equivalents Cash collateral percent of outstanding debt (at least) Line Of Credit Facility, Covenant Terms, Cash Collateral, Percent Of Debt Outstanding Line Of Credit Facility, Covenant Terms, Cash Collateral, Percent Of Debt Outstanding 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 Stock-Based Compensation Share-based Payment Arrangement [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] Revenue Revenue from Contract with Customer, Excluding Assessed Tax 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 Beginning Balance (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 (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Outstanding Ending Balance (in shares) Weighted Average Grant Value Per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Outstanding Beginning Balance (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 (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 Ending Balance (in dollars per share) 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 Receivable Retainage Retention amounts expected to be collected in next twelve months Contract Receivable Retainage, Next Twelve Months Segment Reporting [Abstract] Geographic Information Segment Reporting Disclosure [Text Block] 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] Cash dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Income Tax Disclosure [Abstract] Schedule of Components of Income Tax Provision (Benefit) Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of Income (Loss) Before Income Taxes Schedule of Income before Income Tax, Domestic and Foreign [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 Valuation Allowance Summary of Valuation Allowance [Table Text Block] Reconciliation of Unrecognized Tax Benefits Summary of Income Tax Contingencies [Table Text Block] Deferred Tax Assets: Deferred Tax Assets, Net, Classification [Abstract] Net operating loss Deferred Tax Assets, Operating Loss Carryforwards Credit carryforwards Deferred Tax Assets, Tax Credit Carryforwards Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Pensions Uniform capitalization and inventory Deferred Tax Assets Uniform Capitalization And Inventory Deferred tax assets uniform capitalization and inventory. Stock-based compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Reserve for accrued employee benefits Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits Warranty accrual Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Warranty Reserves Accrued legal Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Postretirement benefits liability Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Postretirement Benefits Goodwill Deferred Tax Assets, Goodwill and Intangible Assets Other Deferred Tax Assets, Other Deferred tax assets Deferred Tax Assets, Gross Deferred Tax Liabilities: Deferred Tax Liabilities, Net, Classification [Abstract] Depreciation and amortization Deferred Tax Liabilities Depreciation And Amortization Deferred tax liabilities depreciation and amortization. Deferred tax liabilities Deferred Tax Liabilities, Gross Less: valuation allowance Deferred Tax Assets, Valuation Allowance Net deferred income tax asset Deferred Tax Assets, Net Business and Organization Nature of Operations [Text Block] Statement of Comprehensive Income [Abstract] Net income (loss) Net Income (Loss) Attributable to Parent Foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Postretirement benefit adjustment, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent September 30, Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Earnings Per Share [Abstract] Denominator: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average basic shares (in shares) Weighted Average Number of Shares Outstanding, Basic Dilutive effect of restricted stock units (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted average diluted shares with assumed conversions (in shares) Weighted Average Number of Shares Outstanding, Diluted Earnings (loss) per share: Earnings Per Share, Basic and Diluted [Abstract] Basic (in dollars per share) Earnings Per Share, Basic Diluted (in dollars per share) Earnings Per Share, Diluted Accounting Policies [Abstract] Revenue from External Customers by Products and Services [Table] Revenue from External Customers by Products and Services [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accounts Receivable Accounts Receivable [Member] Other Assets Other Assets [Member] Revenue from External Customer [Line Items] Revenue from External Customer [Line Items] Retention amounts expected to be collected in next fiscal year Retention amounts expected to be collected in Fiscal 2021 Contract Receivable Retainage, Year Two Long-term contract beginning Long-term Contract, Period Long-term Contract, Period Warranty for parts and services date of shipment Warranty, Parts And Services, Date Of Shipment, Period Warranty, Parts And Services, Date Of Shipment, Period Warranty parts and services date of energization Warranty, Parts And Services, Date Of Energization, Period Warranty, Parts And Services, Date Of Energization, Period Research and development expenses Research and Development Expense Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Recurring [Member] 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 Restricted cash Restricted Cash, Fair Value Disclosure Restricted Cash, Fair Value Disclosure Other assets Deferred Compensation Plan Assets Fair Value Disclosure Deferred compensation plan assets fair value disclosure. Liabilities: Liabilities, Fair Value Disclosure [Abstract] Deferred compensation Deferred Compensation Liability, Current and Noncurrent 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] 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] Revenue from sales orders, percentage Concentration Risk, Percentage Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets by Major Class Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name Finite-Lived Intangible Assets, Major Class Name [Domain] Purchased Technology Purchased Technology [Member] Purchased technology. Supply Agreement Supply Agreement [Member] Supply agreement. Income Statement Location Income Statement Location [Axis] Income Statement Location Income Statement Location [Domain] Other Income Other Income [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Goodwill Goodwill Purchased technology Finite-Lived Intangible Assets, Net Impairment of goodwill Goodwill, Impairment Loss Amortization of intangible assets Amortization of Intangible Assets Useful life of intangible asset Finite-Lived Intangible Asset, Useful Life Cash received from amended supply agreement Cash Received From Amended Supply Agreement Cash received from amended supply agreement. Additional amount paid on execution of agreement Additional Amount Paid On Execution Of Agreement Additional amount paid on execution of agreement. Acquired finite-lived intangible assets, period Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Deferred credit Deferred Revenue and Credits Deferred credit amortization period Finite-Lived Intangible Assets, Remaining Amortization Period Gains in other income Other Nonoperating Income (Expense) Operating Leases Payments Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2020 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2021 Operating Leases, Future Minimum Payments, Due in Two Years 2022 Operating Leases, Future Minimum Payments, Due in Three Years 2023 Operating Leases, Future Minimum Payments, Due in Four Years 2024 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total lease commitments Operating Leases, Future Minimum Payments Due Operating Sublease Income Operating Leases, Sublease Future Minimum Payments Due, Rolling Maturity [Abstract] [Abstract] Operating Leases, Sublease Future Minimum Payments Due, Rolling Maturity [Abstract] [Abstract] 2020 Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due Next Twelve Months Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due Next Twelve Months 2021 Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Two Years Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Two Years 2022 Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Three Years Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Three Years 2023 Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Four Years Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Four Years 2024 Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Five Years Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due In Five Years Thereafter Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due Thereafter Operating Leases, Rent Expense, Sublease Rentals, Future Minimum Payments, Due Thereafter Total lease commitments Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals Principles of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Cash and Investments Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Fair Value of Financial Instruments Fair Value Measurement, Policy [Policy Text Block] Accounts Receivable Accounts Receivable [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Inventories Inventory, Policy [Policy Text Block] Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Warranty Costs Standard Product Warranty, Policy [Policy Text Block] Research and Development Expense Research and Development Expense, Policy [Policy Text Block] Foreign Currency Translation Foreign Currency Transactions and Translations Policy [Policy Text Block] Stock-Based Compensation Share-based Payment Arrangement [Policy Text Block] New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Computation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Contract Assets and Liabilities Contract with Customer, Asset and Liability [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Schedule of Revenues from External Customers by Geographical Areas Revenue from External Customers by Geographic Areas [Table Text Block] Schedule of Long-Lived Assets by Geographical Areas Long-lived Assets by Geographic Areas [Table Text Block] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Forecast Forecast [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 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] Right-of-use asset recorded with adoption of new accounting standards Operating Lease, Right-of-Use Asset Lease liability recorded with adoption of new accounting standards Operating Lease, Liability Schedule of Restricted Stock Units Activity Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block] U.S. Income (Loss) from Continuing Operations before Income Taxes, Domestic Other than U.S. Income (Loss) from Continuing Operations before Income Taxes, Foreign Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Year Ending September 30, Long-term Debt, Fiscal Year Maturity [Abstract] 2020 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2021 Long-term Debt, Maturities, Repayments of Principal in Year Two 2022 Long-term Debt, Maturities, Repayments of Principal in Year Three 2023 Long-term Debt, Maturities, Repayments of Principal in Year Four 2024 Long-term Debt, Maturities, Repayments of Principal in Year Five Total long-term debt maturities Long-term Debt and Lease Obligation Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance at beginning of period Unrecognized Tax Benefits Increases related to tax positions taken during the current period Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Increases related to tax positions taken during a prior period Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Decreases related to expiration of statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Decreases related to settlement with taxing authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Balance at end of period Raw materials, parts and subassemblies Inventory, Raw Materials and Supplies, Gross Work-in-progress Inventory, Work in Process, Gross Provision for excess and obsolete inventory Inventory Valuation Reserves Total inventories Gross assets Gross liabilities and valuation allowance Deferred Tax Liabilities, Gross And Valuation Allowance Deferred Tax Liabilities, Gross And Valuation Allowance Net deferred income tax asset Retirement Benefits [Abstract] Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Axis] Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Axis] Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Domain] Other Postretirement Benefits, Individual Contracts, Type of Deferred Compensation [Domain] Deferred compensation plan Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits [Member] Investment Type [Axis] Investment Type [Axis] Investment [Domain] Investments [Domain] Company owned life insurance policies Company Owned Life Insurance Policies [Member] Company Owned Life Insurance Policies [Member] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Retiree medical plan Postretirement Health Coverage [Member] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Defined contribution plan recognized expenses Defined Contribution Plan, Cost Percentage of employee based salary permitted for deferral under the plan Deferred Compensation Arrangement With Individual Maximum Employee Subscription Rate Deferred compensation arrangement with individual maximum employee subscription rate. Percentage of employee annual bonus permitted for deferral under the plan Deferred Compensation Arrangement With Individual Maximum Contractual Amount Bonus Deferred compensation arrangement with individual maximum contractual amount bonus. Deferred compensation expense adjustment Deferred Compensation Arrangement With Individual Compensation Adjustment Income Expense Deferred compensation arrangement with individual compensation adjustment income (expense). Deferred compensation plan assets Deferred Compensation Plan Assets Deferred compensation liability Deferred compensation, retirement age Deferred Compensation Arrangement With Individual, Age Of Individual Deferred Compensation Arrangement With Individual, Age Of Individual Deferred compensation requisite service period Deferred Compensation Arrangement with Individual, Requisite Service Period Deferred compensation recorded liability Deferred Compensation Arrangement with Individual, Recorded Liability Cash surrender value of life insurance Cash Surrender Value of Life Insurance Age older but less than Defined Benefit Plan, Employee Coverage, Age Of Individual Defined Benefit Plan, Employee Coverage, Age Of Individual Unfunded liability Defined Benefit Plan, Funded (Unfunded) Status of Plan Net periodic postretirement benefit cost (less than) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Earnings Per Share Earnings Per Share [Text Block] 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 (used in) 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 (recovery) Deferred income taxes Deferred Income Taxes and Tax Credits Gain on amended supply agreement Gain (Loss) on Disposition of Intangible Assets Gain on cash surrender value of life insurance Gain (Loss) On Cash Surrender Value Of Life Insurance Gain (Loss) On Cash Surrender Value Of Life Insurance 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 (used in) 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 Proceeds from life insurance policy Proceeds from Life Insurance Policy Net cash provided by (used in) 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 (decrease) 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 Income Taxes Income Tax Disclosure [Text Block] Cash paid (received) during the period for: Supplemental Cash Flow Information [Abstract] Interest paid, net of interest income Interest Paid, Net Of Interest Income Interest Paid, Net Of Interest Income Income taxes paid, net of refunds Income Taxes Paid, Net Non-cash capital expenditures Capital Expenditures Incurred but Not yet Paid Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Surety Bond 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. Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Rent expense Operating Leases, Rent Expense, Net Additional bonding capacity Commitments And Contingencies Additional Bonding Capacity Commitments and contingencies additional bonding capacity. Loss contingency, estimate of actual or projected loss Loss Contingency, Estimate of Possible Loss Probable liquidated damages Loss Contingency Probable Loss In Period Loss contingency probable loss in period. Failure to meet contractual commitments, reduction to revenue Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Schedule of Revenues from External Customers and Long-Lived Assets [Table] Schedule of Revenues from External Customers and Long-Lived Assets [Table] Middle East and Africa Middle East And Africa [Member] Middle East And Africa [Member] Far East FAR EAST [Member] FAR EAST [Member] Europe Europe [Member] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues from External Customers and Long-Lived Assets [Line Items] Revenues Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward] Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward] Balance at beginning of period Increase to warranty expense Standard and Extended Product Warranty Accrual, Increase for Warranties Issued 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 Revenue Revenue from Contract with Customer [Text Block] Revenues Revenue from Contract with Customer, Including Assessed Tax Gross profit Gross Profit Earnings (loss) per share: Revenue, 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] Revenue, remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period 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) Current income tax provision Current Income 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) Deferred income tax provision Deferred Income Tax Expense (Benefit) Total income tax provision (benefit) Income Tax Expense (Benefit) Subsequent Events Subsequent Events [Text Block] Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Lease expense Sublease income from third parties Operating Leases, Rent Expense, Sublease Rentals Statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent State income taxes, net of federal benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Research and development credit Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent Foreign rate differential Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent Foreign withholding Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Percent Foreign valuation allowance Effective Income Tax Rate Reconciliation Change In Foreign Valuation Allowance Effective income tax rate reconciliation change in foreign valuation allowance. NOL carryback impact on deductions Effective Income Tax Rate Reconciliation NOL Carryback Impact On Deductions, Percent Effective Income Tax Rate Reconciliation NOL Carryback Impact On Deductions, Percent Deferred tax rate differential Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent Other Effective Income Tax Rate Reconciliation,Other Reconciling Items, Percent Effective rate Effective Income Tax Rate Reconciliation, Percent Valuation Allowance [Table] Valuation Allowance [Table] Valuation Allowances and Reserves Type SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain] Valuation Allowance of Deferred Tax Assets SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset [Member] Valuation Allowance [Line Items] Valuation Allowance [Line Items] SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] Beginning balance SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount Charged to cost and expenses Valuation Allowances And Reserves Charged Or Credited To Cost And Expense Valuation allowances and reserves charged or credited to cost and expense. Charged to other accounts Valuation Allowances And Reserves Charged Or Credited To Other Accounts Valuation allowances and reserves charged or credited to other accounts. Ending balance Change in contract estimates related to projects in progress Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Industrial development revenue bonds Less: current portion Long-term Debt and Lease Obligation, Current Total long-term debt Supplemental Disclosures of Cash Flow Information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Income Statement [Abstract] Cost of goods sold Cost of Goods and Services Sold Gross profit Selling, general and administrative expenses Selling, General and Administrative Expense Insurance proceeds Insurance Recoveries Restructuring, separation and other expenses, net Restructuring Charges Operating income (loss) Operating Income (Loss) Other income (Note F) Interest expense Interest Expense Interest income Investment Income, Interest Income tax provision (benefit) Net income (loss) Weighted average shares: Basic (in shares) Diluted (in shares) Dividends per share (in dollars per share) Income Tax Contingency [Table] Income Tax Contingency [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] International Foreign Tax Authority [Member] Tax Credit Carryforward Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name Tax Credit Carryforward, Name [Domain] R&D Tax Credit Research And Development Tax Credit [Member] Research and development tax credit. Income Tax Contingency [Line Items] Income Tax Contingency [Line Items] Blended tax rate Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent Effective tax rate Tax expense Effective Income Tax Rate Reconciliation, Tax Settlement, Domestic, Amount Retroactive tax benefit Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Undistributed earnings of foreign subsidiaries Undistributed Earnings of Foreign Subsidiaries Tax credit carryforwards Tax Credit Carryforward, Amount Operating loss carryforwards Operating Loss Carryforwards Valuation allowance related to deferred tax assets Decrease in unrecognized tax benefits due to expiration of certain federal statutes of limitations Decrease in Unrecognized Tax Benefits is Reasonably Possible Refund related to U.S. federal carryback claim Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority Fair Value Measurements Fair Value Disclosures [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Schedule of Quarterly Financial Information Quarterly Financial Information [Table Text Block] 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 Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers 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 Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Detail of Selected Balance Sheet Accounts Supplemental Balance Sheet Disclosures [Text Block] Statement of Stockholders' Equity [Abstract] Postretirement benefit adjustment, tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] United Kingdom UNITED KINGDOM Long-Term Debt Long-term Debt [Text Block] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Statement [Table] Statement [Table] Equity Components Equity Components [Axis] Equity Component Equity Component [Domain] 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] Beginning balance (in shares) Common Stock, Shares, Outstanding Beginning balance Net (loss) income 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 Ending balance (in shares) Ending balance Gross Carrying Value Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Net Carrying Value Allowance for doubtful accounts 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 (in shares) Treasury Stock, Shares