Document And Entity Information [Abstract] Document And Entity Information [Abstract] Document Information [Table] Class of Stock [Axis] Class of Stock [Domain] Document Information [Line Items] Document Type Amendment Flag Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Trading Symbol Entity Common Stock, Shares Outstanding Statement of Financial Position [Abstract] Statement [Table] Statement [Line Items] Assets [Abstract] ASSETS Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Beginning of period End of period Accounts Receivable, Net, Current Accounts receivable, net of allowances of $568 and $605, respectively Costs in Excess of Billings, Current Costs and estimated earnings in excess of billings on uncompleted contracts Contract assets Insurance Settlements Receivable, Current Current portion of receivable for insurance claims in excess of deductibles Income Taxes Receivable, Current Refundable income taxes, net Other Assets, Current Other current assets Assets, Current Total current assets Property, Plant and Equipment, Net Property and equipment, net of accumulated depreciation of $242,985 and $231,391, respectively Goodwill Goodwill Intangible Assets, Net (Excluding Goodwill) Intangible assets, net of accumulated amortization of $5,423 and $5,183, respectively Insurance Settlements Receivable, Noncurrent Receivable for insurance claims in excess of deductibles Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Investment in joint ventures Other Assets, Noncurrent Other assets Assets Total assets Liabilities [Abstract] LIABILITIES AND STOCKHOLDERS' EQUITY Liabilities, Current [Abstract] Current liabilities: Capital Lease Obligations, Current Current portion of capital lease obligations Less: Current portion of capital lease obligations Accounts Payable, Current Accounts payable Billings in Excess of Cost, Current Billings in excess of costs and estimated earnings on uncompleted contracts Contract liabilities Billings in excess of costs and estimated earnings on uncompleted contracts Self Insurance Reserve, Current Current portion of accrued self-insurance Accrued Income Taxes, Current Income taxes payable, net Other Liabilities, Current Other current liabilities Liabilities, Current Total current liabilities Deferred Tax Liabilities, Net, Noncurrent Deferred income tax liabilities Long-term Debt, Excluding Current Maturities Long-term debt Self Insurance Reserve, Noncurrent Accrued self-insurance Capital Lease Obligations, Noncurrent Capital lease obligations, net of current maturities Long-term capital lease obligations Other Liabilities, Noncurrent Other liabilities Liabilities Total liabilities Commitments and Contingencies Commitments and contingencies Stockholders' Equity Attributable to Parent [Abstract] Stockholders' equity: Preferred Stock, Value, Outstanding Preferred stock—$0.01 par value per share; 4,000,000 authorized shares; none issued and outstanding at June 30, 2018 and December 31, 2017 Common Stock, Value, Issued Common stock—$0.01 par value per share; 100,000,000 authorized shares; 16,565,333 and 16,464,757 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively Additional Paid in Capital, Common Stock Additional paid-in capital Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive loss Retained Earnings (Accumulated Deficit) Retained earnings Stockholders' Equity Attributable to Parent Total stockholders' equity Liabilities and Equity Total liabilities and stockholders' equity Allowance for Doubtful Accounts Receivable, Current Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Finite-Lived Intangible Assets, Accumulated Amortization Preferred Stock, Par or Stated Value Per Share Preferred Stock, Shares Authorized Preferred Stock, Shares Issued Preferred Stock, Shares Outstanding Common Stock, Par or Stated Value Per Share Common Stock, Shares Authorized Common Stock, Shares, Issued Common Stock, Shares, Outstanding Income Statement [Abstract] Legal Entity [Axis] Entity [Domain] Gross Profit Gross profit Selling, General and Administrative Expense Selling, general and administrative expenses Amortization of Intangible Assets Amortization of intangible assets Gain (Loss) on Disposition of Property Plant Equipment Gain on sale of property and equipment Gain on sale of property and equipment Operating Income (Loss) Income from operations Income from operations Nonoperating Income (Expense) [Abstract] Other income (expense) Investment Income, Interest Interest income Interest Expense Interest expense Other Nonoperating Income (Expense) Other, net Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income before provision for income taxes Income Tax Expense (Benefit) Income tax expense Net Income (Loss) Attributable to Parent Net income Net income Net income Net income Earnings Per Share [Abstract] Income per common share: Earnings Per Share, Basic - Basic (in dollars per share) Income per common share, basic Earnings Per Share, Diluted - Diluted (in dollars per share) Income per common share, diluted Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average number of common shares and potential common shares outstanding: Weighted Average Number of Shares Outstanding, Basic - Basic (in shares) Weighted average common shares outstanding Weighted Average Number of Shares Outstanding, Diluted - Diluted (in shares) Weighted average common shares outstanding, diluted Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Foreign currency translation adjustment Other Comprehensive Income (Loss), Net of Tax Other comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent, Total Total comprehensive income Revenue from Contract with Customer, Excluding Assessed Tax Contract revenues Cost of Goods and Services Sold Contract costs Statement of Cash Flows [Abstract] Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents Cash and Cash Equivalents, at Carrying Value [Abstract] Cash and cash equivalents: Net Cash Provided by (Used in) Operating Activities [Abstract] Cash flows from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash flows provided by operating activities: Depreciation Depreciation and amortization of property and equipment Share-based Compensation Stock-based compensation expense Deferred Income Tax Expense (Benefit) Deferred income taxes Other Noncash Income (Expense), Total Other non-cash items Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities Increase (Decrease) in Accounts Receivable Accounts receivable, net Increase (Decrease) in Unbilled Receivables Costs and estimated earnings in excess of billings on uncompleted contracts Increase (Decrease) in Insurance Settlements Receivable Receivable for insurance claims in excess of deductibles Increase (Decrease) in Other Operating Assets Other assets Increase (Decrease) in Accounts Payable Accounts payable Increase (Decrease) in Billing in Excess of Cost of Earnings Billings in excess of costs and estimated earnings on uncompleted contracts Increase (Decrease) in Self Insurance Reserve Accrued self insurance Increase (Decrease) in Other Operating Liabilities Other liabilities Net Cash Provided by (Used in) Operating Activities Net cash flows provided by operating activities Net Cash Provided by (Used in) Investing Activities [Abstract] Cash flows from investing activities: Proceeds from Sale of Property, Plant, and Equipment Proceeds from sale of property and equipment Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment Net Cash Provided by (Used in) Investing Activities Net cash flows used in investing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities Net cash flows used in financing activities Effect of Exchange Rate on Cash Effect of exchange rate changes on cash Proceeds from (Repayments of) Lines of Credit Net repayments under revolving lines of credit Repayments of Long-term Capital Lease Obligations Payment of principal obligations under capital leases Proceeds from Stock Options Exercised Proceeds from exercise of stock options Payments for Repurchase of Common Stock Repurchase of common shares Proceeds from (Payments for) Other Financing Activities Other financing activities Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Text Block] Fair Value Disclosures [Abstract] Fair Value Disclosures [Text Block] Contractors [Abstract] Long-term Contracts or Programs Disclosure [Text Block] Debt Disclosure [Abstract] Debt Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Tax Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments Contingencies and Guarantees [Text Block] Leases [Abstract] Leases of Lessee Disclosure [Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Segment Reporting [Abstract] Segment Reporting Disclosure [Text Block] Earnings Per Share [Text Block] Subsequent Events [Abstract] Subsequent Events [Text Block] Organization and Business [Policy Text Block] The entire disclosure represents the organization and subsidiaries information. Consolidation, Policy [Policy Text Block] Foreign Currency Transactions and Translations Policy [Policy Text Block] Trade and Other Accounts Receivable, Policy [Policy Text Block] Use of Estimates, Policy [Policy Text Block] New Accounting Pronouncements, Policy [Policy Text Block] Schedule of Revenue by Contract Type Schedule of Revenue by Contract Type [Table Text Block] Tabular disclosure of the revenue by contract type. Schedule of Revenue by Market Type [ ] Schedule of Revenue by Market Type [Table Text Block] Tabular disclosure of the revenue by market type. Contract with Customer, Asset and Liability [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Financial Statements [Axis] Financial Statements [Domain] Consolidated Balance Sheet [Member] Costs in Excess of Billings and Billings in Excess of Costs [Table Text Block] Schedule of Future Minimum Lease Payments for Capital and Operating Leases [Table Text Block] Tabular disclosure of future minimum lease payments as of the date of the latest balance sheet presented, in aggregate and for each of the five years succeeding fiscal years, with separate deductions from the total for the amount representing executor costs, including any profit thereon, included in the minimum lease payments and for the amount of the imputed interest necessary to reduce the net minimum lease payments to present value. Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Organization Consolidation and Presentation of Financial Statements [Table] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate, Type [Domain] Estimate Adjustment [Member] Restatement [Axis] Restatement [Domain] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Customer [Axis] Customer [Domain] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Equity Components [Axis] Equity Component [Domain] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Principles, Early Adoption [Domain] Income Statement Location [Axis] Income Statement Location [Domain] Recognized Revenues [Axis] Recognized Revenues [Domain] Significant Change Orders Or Claims [Member] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Organization Consolidation and Presentation of Financial Statements [Line Items] Cost Estimate Revision Gross Margin Increase Decrease Percentage Cost Estimate Revision Gross Margin Increase (Decrease) Percentage Percentage of increase decrease cost estimate revision gross margin. Revenues Amount Foreign Currency Transaction Gain (Loss), Unrealized Foreign Currency Transaction Gain (Loss) Segments [Axis] Segments [Domain] Transmission and Distribution [Member] T&D [Member] T&D [Member] Commercial and Industrial [Member] C&I [Member] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Domain] Fixed-price Contract [Member] Contract Type Fixed price [Member] Unit Price Contract [Member] Contract Type Unit Price [Member] TE Contract [Member] Contract Type T&E [Member] Other Contract [Member] Contract Type Other [Member] Contract with Customer, Sales Channel [Axis] Contract with Customer, Sales Channel [Domain] Concentration Risk, Percentage Percent Market Type Transmission [Member] Market Type Distribution [Member] Market Type Electrical Construction [Member] Net Period [Axis] Net Period [Domain] Net Period Change [Member] Contract with Customer, Liability [Abstract] Contract Liabilities Net Contract Assets Liabilities Net contract assets (liabilities) The amount of net contract assets(liabilities) as at balance sheet period. Increase (Decrease) in Cost in Excess of Billing on Uncompleted Contract Contract assets Increase (Decrease) in Payables to Customers Contract liabilities IncreaseDecreasein net contract assets liabilities Net contract assets (liabilities) The amount of increase(decrease)in net contract assets(liabilities) during the year. Revenue, Remaining Performance Obligation Total, Remaining Performance Obligation Revenue, Remaining Performance Obligation Not Be Recognized Within Twelve Months Amount estimated to not be recognized within 12 months Amount of transaction price allocated to performance obligation that has not been recognized as revenue within 12 months. Accounting Standards Update 2014-09 [Member] Restatement Adjustment [Member] Increase in Revenue The increase amount of revenue during the year. Contract with Customer, Liability, Revenue Recognized Contracts in Process [Table] Contracts in Process [Line Items] Aggregate Costs Incurred On Uncompleted Contracts And Estimated Earnings Costs and estimated earnings on uncompleted contracts Represents the aggregate of costs incurred on uncompleted contracts and estimated earnings. Billings To Date Less: Billings to date Represents the billings to date on uncompleted contracts accounted for under the percentage-of-completion method. Net Costs And Estimated Earnings In Excess Of Billings Net asset position for contracts in process Represents the net costs and estimated earnings in excess of billings on uncompleted contracts accounted for under the percentage-of-completion method. Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Syndicated Credit Agreement [Member] Credit Agreement [Member] Debt Instrument [Axis] Debt Instrument, Name [Domain] Foreign Revolving Loans and Letters of Credit [Member] Range [Axis] Range [Domain] Maximum [Member] Minimum [Member] Variable Rate [Axis] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) [Member] Base Rate [Member] Credit Facility [Axis] Credit Facility [Domain] Revolving Credit Facility [Member] Performance letters of credit [Member] Two Thousand Sixteen Credit Facility [Member] Facility [Member] Non-performance Letters Of Credit [Member] Liability Class [Axis] Fair Value by Liability Class [Domain] Insurance Program Obligations [Member] Insurance Program Obligations Contract Performance Obligations [Member] Debt Instrument [Line Items] Line Of Credit Facility Option To Increase Maximum Borrowing Capacity Option to increase borrowing capacity Represents the option to increase maximum borrowings on the credit facility. Line of Credit Facility, Maximum Borrowing Capacity Maximum borrowing capacity Letter Of Credit Fees Percentage Letter of credit fee (as a percent) Represents the fees for the letter of credit facility, expressed as a percentage. Debt Instrument, Basis Spread on Variable Rate Interest rate margin (as a percent) Debt Instrument Covenant Interest Coverage Ratio Interest coverage ratio Represent the minimum interest coverage ratio under the credit agreement. Letters of Credit Outstanding, Amount Long-term Line of Credit Percentage of Capital Stock From Direct Foreign Subsidiaries Percentage of capital stock from direct foreign subsidiaries pledged as collateral for a debt. Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Maximum Acquisition Consideration Under Credit Agreement Maximum consideration for acquisitions under the credit agreement allows the expansion of the Leverage Ratio. Debt Issuance Costs, Line of Credit Arrangements, Net Debt Instrument Covenant Leveraged Debt Ratio Restriction Threshold of debt coverage ration at which the credit agreement restricts certain types of payments. Debt, Weighted Average Interest Rate Leverage Coverage Ratio Expansion The Company has the option to expand the debt coverage ratio to 3.5 in the event of an acquisition in excess of $30 million. The expansion occurs in the quarter the acquisition is consummated and shall continue in effect for the next four consecutive quarters. Leverage Coverage Ratio The Company has the option to expand the debt coverage ratio in the event of an acquisition. Effective Income Tax Rate Reconciliation, Percent [Abstract] Income Taxes [Table] Income Tax Authority [Axis] Income Tax Authority [Domain] Tax Benefit Stock Compensation [Member] Tax Benefit Stock Compensation Scenario [Axis] Scenario, Unspecified [Domain] Income Taxes [Line Items] Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent U.S. federal statutory tax rate (as a percent) Effective Income Tax Rate Reconciliation, Percent Unrecognized Tax Benefit Including Tax Interest Accrued The gross amount of unrecognized tax benefits, including interest, pertaining to uncertain tax positions taken in tax returns as of the balance sheet date. Current Federal Tax Expense (Benefit) Other Commitments [Table] Litigation Case [Axis] Litigation Case [Domain] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Other Commitments [Line Items] Loss Contingency Insurance Policy Deductible for Each Line of Coverage Excluding Wildfire and Health Represents the amount of deductible up to the claim aggregate under insurance arrangements, for each line of coverage, excluding wildfire and health insurance. Loss Contingency Insurance Policy Deductible for Wildfire Represents the amount of deductible under wildfire insurance for qualified claims. Outstanding Performance Bonds The total amount of outstanding performance bonds. Estimated Cost to Complete Bonded Projects Estimated cost to complete bonded projects. Purchase Commitment, Remaining Minimum Amount Committed Loss Contingency Health Insurance Deductible For Qualified Individuals Represents the amount of deductible under health insurance benefits for qualified individuals. Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Capital Lease Obligations Capital Leases, Future Minimum Payments, Remainder of Fiscal Year Remainder of 2018 Capital Leases, Future Minimum Payments Due, Next Twelve Months 2019 Capital Leases, Future Minimum Payments Due in Two Years 2020 Capital Leases, Future Minimum Payments Due in Three Years 2021 Capital Leases, Future Minimum Payments Due in Four Years 2022 Capital Leases, Future Minimum Payments Due Thereafter Thereafter Capital Leases, Future Minimum Payments Due, Total Total minimum lease payments Capital Leases, Future Minimum Payments, Interest Included in Payments Interest Capital Leases, Future Minimum Payments, Present Value of Net Minimum Payments, Total Net present value of minimum lease payments OperatingLeasesFutureMinimumPaymentsDueAbstract [Abstract] Operating Lease Obligations Operating Leases, Future Minimum Payments, Remainder of Fiscal Year Remainder of 2018 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2019 Operating Leases, Future Minimum Payments, Due in Two Years 2020 Operating Leases, Future Minimum Payments, Due in Three Years 2021 Operating Leases, Future Minimum Payments, Due in Four Years 2022 Operating Leases, Future Minimum Payments, Due Thereafter Thereafter Operating Leases, Future Minimum Payments Due, Total Total minimum lease payments Capital Leases, Balance Sheet, Assets by Major Class, Net, Total Capital Lease Obligations Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Equity Award [Domain] Restricted Stock [Member] Restricted Awards [Member] Performance Shares [Member] Performance awards [Member] Performance awards [Member] Market based Performance Awards [Member] Internal Measure based Performance Awards [Member] Restricted Stock Units (RSUs) [Member] Trading Activity [Axis] Trading Activity, by Type [Domain] Plan Name [Axis] Plan Name [Domain] Long-Term Incentive Plan [Member] Option Indexed to Issuer's Equity, Type [Axis] Option Indexed to Issuer's Equity, Type [Domain] Title of Individual [Axis] Relationship to Entity [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted-Average Grant Date Fair Value Share Based Compensation Arrangement By Share Based Payment Award Potential Payout As Percentage Of Target Shares Potential Payout As a Percentage of Target Shares The percentage of target shares, an employee can earn, under the plan. Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Abstract] Other information Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Reversal of Share Based Compensation The aggregate amount of noncash, equity-based employee remuneration which is reversed during the period. Segment [Table] TD [Member] T&D [Member] CI [Member] C&I [Member] Corporate Segment [Member] General Corporate [Member] Segment Reporting Information [Line Items] Revenue from Contract with Customer, Including Assessed Tax Contract revenues Contract revenues Subsegments [Axis] Subsegments [Domain] Geographical [Axis] Geographical [Domain] Canadian Operation [Member] Earinings Per Share [Table] Earnings Per Share [Line Items] Net Income (Loss) Attributable to Parent [Abstract] Numerator: Weighted Average Number of Shares Outstanding, Basic [Abstract] Denominator: Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average dilutive securities Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] RestrictedStock [Member] Restricted stock [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Subsequent Event [Line Items] Business Combination, Acquisition Related Costs Payments to Acquire Businesses, Gross Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Huen Electric Inc [Member] HuenElectricIncMember Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event [Member]