Performance Period [Domain] Performance period pertaining to equity-based compensation. Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Performance Period Performance period Represents the performance period of other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Performance Measure [Axis] Information by performance measure type pertaining to equity-based compensation. Performance Measure [Domain] Performance measure type pertaining to equity-based compensation. Represents information pertaining to return-on-invested-capital. Return on Equity [Member] ROE Return on Invested Capital [Member] ROIC Represents information pertaining to relative total-shareholder-return. Total Shareholder Return [Member] TSR Represents information pertaining to return-on-equity. Performance Period Prior to January 01 2014 [Member] Prior to January 1, 2014 Represents information pertaining to performance period prior to January 1, 2014. Performance Period Prior to December 31 2016 [Member] Prior to December 31, 2016 Represents information pertaining to performance period prior to December 31, 2016. Loss Contingency Compensatory Damages Awarded Value Compensatory damages Represents the amount of the compensatory damages award that was returned against the defendants in the legal matter. Amendment Description Loss Contingency Estimated Punitive Damages that can be Sought Maximum Maximum estimated punitive damage awards Represents the maximum estimated amount of the punitive damages award that can be sought by the plaintiff in the legal matter. Amendment Flag Reserve for Legal Settlements Reserve for legal settlements Represents the amount of reserve established for expense relating to settlement of litigation. Legal Settlements Legal settlements Represents the amount of expense provided for settlement of litigation during the period. Schedule of Roll Forward Activity in Insurance Reserves [Table Text Block] Schedule of roll forward activity in the insurance reserve Tabular disclosure of roll forward activity in the insurance reserve. Operating lease, additional disclosure Operating Lease, Additional Disclosure [Abstract] Loss Contingency, Insurance Expense Insurance expense Represents the insurance expenses, including premiums, for workers' compensation, general liability, automobile liability and employee health benefits. Share Based Compensation Arrangement by Share Based Payment Award, Options, Aggregate Intrinsic Value [Abstract] Aggregate Intrinsic Value Share Based Compensation Arrangement by Share Based Payment Award, Options, Vested in Period, Total Fair Value Fair value of options vested The total fair value of stock options vested during the reporting period. Range of Exercise Prices from Dollars 3.65 to 9.00 [Member] Exercise Price Ranges, $3.65-$9.00 Represents the range of exercise price from 3.65 dollars per share to 9.00 dollars per share. Exercise Price Ranges, $9.01-$18.00 Represents the range of exercise price from 9.01 dollars per share to 18.00 dollars per share. Range of Exercise Price from Dollars 9.01 to 18.00 [Member] Range of Exercise Prices from Dollars 18.01 to 24.18 [Member] Exercise Price Ranges, $18.01-$24.18 Represents the range of exercise price from 18.01 dollars per share to 24.18 dollars per share. Share Based Compensation Shares Authorized under Stock Option Plans, Exercise Price Range Outstanding Options [Abstract] Options Outstanding Share Based Compensation Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options [Abstract] Options Exercisable 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 Percentage of Target Awards Earned Target awards earned during the performance period (as a percent) Represents the percentage of target awards earned for the performance period. Share Based Compensation Arrangement by Share Based Payment Award, Exercisable Period from Date of Grant Exercisable period from date of grant Represents the period, from the date of grant, that award can be exercised once they have vested. Schedule of Defined Contribution Plans [Table] Disclosures about defined contribution plans. Current Fiscal Year End Date Award Type [Axis] Defined Contribution Plans [Axis] Information by defined contribution plans. Syndicated Credit Agreement [Member] Credit Agreement A contractual arrangement with a lender consisting of a syndicated credit agreement. Swingline Loans [Member] Swingline loans Represents information pertaining to the swingline loan, a loan that grants institutions access to large amounts of cash in order to cover possible shortfalls from other debt commitments. Debt Instrument, Variable Rate Base, Alternate Base Rate [Member] ABR The alternate base rate used to calculate the variable interest rate of the debt instrument. Debt Instrument, Variable Rate Base, Federal Funds Effective Rate [Member] Federal Funds Effective Rate The federal funds effective rate used to calculate the variable interest rate of the debt instrument. 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. Letter of credit fee (as a percent) Represents the fees for the letter of credit facility, expressed as a percentage. Letter of Credit Fees Percentage Letter of Credit Fronting Fees Facing fees (as a percent) The percentage of fronting fees paid on the outstanding amount of letters of credit. Schedule of Deferred Tax Assets and Liabilities, Balance Sheet Classification [Table Text Block] Schedule of balance sheet classification of deferred income taxes Tabular disclosure of the balance sheet classification of deferred income taxes. Effective Income Tax Rate Reconciliation Provision to Return Adjustments Net Provision to return adjustments, net (as a percent) The sum of the differences between the effective income tax rate and domestic federal statutory income tax rate attributable to provision to return adjustments. Income Tax Examination Federal Income Tax Settlements Period under Examination Period under examination Represents the period for which the entity's federal tax returns are subject to examination. Document Period End Date Unrecognized Tax Benefits Including Tax Interest Accrued Total liability for unrecognized tax benefits The gross amount of unrecognized tax benefits, including interest, pertaining to uncertain tax positions taken in tax returns as of the balance sheet date. Schedule of Intangible Assets and Goodwill [Table] Disclosure of goodwill and intangible assets, which may be broken down by segment or major class. Goodwill and Other Intangible Assets Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Schedule of Intangible Assets and Goodwill [Line Items] Additional Information of Intangible Assets [Abstract] Additional information on intangible assets Stock Issued Shares in Lieu of Director Retainer Stock issued in lieu of director retainer (in shares) Represents the number of shares issued in lieu of director retainer. Organization, Business and Basis of Presentation. Document and Entity Information The entire disclosure for new accounting pronouncements that have been issued but not yet adopted, and new accounting pronouncements adopted. New Accounting Pronouncements [Text Block] Recently Issued and Adopted Accounting Pronouncements Schedule of net asset (liability) position for contracts in process Tabular disclosure of costs and estimated earnings on uncompleted contracts, from their inception, and related amounts billed. Long Term Contracts or Programs [Table Text Block] Entity [Domain] Tabular disclosure of the net of 1) costs and estimated earnings in excess of related billings on uncompleted contracts and 2) billings in excess of costs and estimated earnings on uncompleted contracts included in the consolidated balance sheet. Long Term Contracts or Programs Net Costs and Estimated Earnings in Excess of Billings [Table Text Block] Schedule of net asset (liability) position for contracts in process included in consolidated balance sheets Net asset (liability) position for contracts in process Costs and Estimated Earnings on Uncompleted Contracts or Programs [Abstract] Represents the aggregate of costs incurred on uncompleted contracts and estimated earnings. Aggregate Costs Incurred on Uncompleted Contracts and Estimated Earnings Costs and estimated earnings on uncompleted contracts 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 Represents the net costs and estimated earnings in excess of billings on uncompleted contracts accounted for under the percentage-of-completion method. Net Costs and Estimated Earnings in Excess of Billings Remaining term of operating lease Represents the remaining term of the operating lease arrangements of the entity. Operating Lease Remaining Term Number of irrevocable standby letters of credit outstanding Represents the number of irrevocable standby letters of credit outstanding. Number of Letters of Credit Outstanding Represents the number of letters of credit related to the payment obligation under insurance programs. Number of Letters of Credit Outstanding Related to Payment Obligation under Insurance Programs Number of letters of credit related to the payment obligation under insurance programs Letters of credit outstanding related to contract performance obligations Represents the amount of the letters of credit related to contract performance obligations. Letters of Credit Outstanding Amount Related to Contract Performance Obligations Letters of credit outstanding related to the payment obligation under insurance programs Letters of Credit Outstanding Amount Related to Payment Obligation under Insurance Programs Represents the letters of credit outstanding related to the payment obligation under insurance programs. Deductible per claim for each line of coverage, excluding health Represents the amount of deductible up to the claim aggregate under insurance arrangements, for each line of coverage excluding auto liability and medical insurance, excluding health insurance. Loss Contingency Insurance Policy Deductible for Each Line of Coverage Excluding Health Deductible per claim, once a policy's claim aggregate is reached per line of coverage Represents the amount of deductible under insurance arrangements, once the policy's claim aggregate is reached for each line of coverage, excluding medical insurance. Loss Contingency Insurance Policy Deductible if Claim Aggregate Reached Per Line of Coverage Deductible under health insurance benefits for qualified individuals Represents the amount of deductible under health insurance benefits for qualified individuals. Loss Contingency Health Insurance Deductible for Qualified Individuals Purchase Commitments for Construction Equipment Purchase Commitments [Abstract] Employees [Member] Various employees Represents the various employees, which may include the company's named executive officers. Represents information pertaining to the 2007 Long-term Incentive Plan. Long Term Incentive Plan 2007 [Member] LTIP Number of equity compensation plans Represents the number of share-based compensation plans approved by the entity's shareholders. Share Based Compensation Arrangement by Share Based Payment Award Number of Plans Transmission and Distribution [Member] T&D Represents the Transmission and Distribution ("T&D"), a reportable segment of the entity. C&I Represents the Commercial and Industrial ("C&I"), a reportable segment of the entity. Commercial and Industrial [Member] Number of Multiemployer Plans Withdrawal that Could Result in Assessment of Additional Contribution Liabilities Related to Underfunding of Plans Minimum Number of multi-employer pension plans, the withdrawal of which could result in assessment of liabilities for additional contributions related to the underfunding of plans, minimum Represents the minimum number of multi-employer pension plans from the withdrawal of which a subsidiary could be assessed for liabilities for additional contributions related to the underfunding of plans. Potential Adverse Outcome Number of Litigation Claims Minimum Potential number of litigation claims in which an adverse outcome could result, minimum Represents the minimum potential number of litigation claims in which an adverse outcome could result. Scheduled period of time for cash outlay requirements Represents the schedule period of time for cash outlay requirements under an existing purchase commitment. Significant Purchase Commitment, Scheduled Period of Time for Cash Outlay Insurance [Policy Text Block] Insurance Describes an entity's accounting policy for insurance. Warranty period, maximum Represents the maximum term of warranty typically provided to customers. Maximum Warranty Period Accounts Receivable, Maximum Collection Period of Majority of Customer Balances Maximum collection period of majority of customer balances Represents the maximum accounts receivable period within which majority of customer balances are collected. Minimum Term of Some Larger Contracts Minimum term of some larger contracts Represents the minimum term of some larger contracts. Represents the maximum period for settlement of majority of balances under construction contract. Maximum Period for Settlement of Majority of Balances under Construction Contract Maximum period for settlement of majority of balances under construction contract Classification of Construction Contract [Abstract] Classification of Construction Contract-related Assets and Liabilities Building, Building Improvements and Land Improvements [Member] Buildings and improvements, including land improvements Facility held for productive use including, but not limited to, office, production, storage and distribution facilities and any addition, improvement, or renovation to the structure, for example, but not limited to, interior masonry, interior flooring, electrical, and plumbing. Also including additions or improvements to real estate held. Buildings and improvements Construction Equipment [Member] Construction equipment Represents the construction equipment, including large tool purchases. Insurance Policies [Table] Tabular disclosure representing information related to insurance policies. Insurance Policies [Line Items] Insurance Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Insurance Policies, Deductible Per Claim for Each Line of Coverage Deductible for each line of coverage Amount of risk retained by the entity per claim before the insurance arrangement begins to provide coverage for each line of coverage under insurance arrangements. Insurance Policies, Deductible if Claim Aggregate Reaches Per Line of Coverage Deductible for policies whose claim aggregate reaches per line of coverage Represents the amount of deductible for policies whose claim aggregate reaches per line of coverage. Represents the amount of deductible under health insurance benefits for qualified individuals. Health Insurance, Deductible for Qualified Individuals Deductible under health insurance benefits for qualified individuals One Largest Customer [Member] One customer Represents one largest customer in relation to accounts receivable of the entity. Represents two largest customers in relation to accounts receivable of the entity. Two Largest Customer [Member] Two customers Ten Largest Customer [Member] Ten customers Represents ten largest customers in relation to revenues of the entity. Dominion Resources Inc [Member] Dominion Resources, Inc. Represents Dominion Resources Inc., one of the customers of the entity. National Grid [Member] National Grid Represents National Grid, one of the customers of the entity. Number of Customers, Individually Exceeding 10 Percent Consolidated Accounts Receivable Number of customers individually exceeding 10.0% of consolidated accounts receivable Represents the number of customers individually exceeding 10 percent of consolidated accounts receivable. Schedule of Roll Forward Activity of Allowance for Doubtful Accounts [Table Text Block] Schedule of roll-forward activity of allowance for doubtful accounts Tabular disclosure of roll-forward activity of allowance for doubtful accounts during the period. Intangible Assets, Gross, Including Goodwill Gross carrying amount of goodwill and other intangible assets Gross amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Defined Contribution Plans [Domain] The name of the defined contribution plan or a description of the plans grouped. Entity Well-known Seasoned Issuer Profit Sharing and Thrift Employee Benefit Plan [Member] Profit sharing and thrift employee benefit plan Represents information pertaining to profit sharing and thrift employee benefit plan in effect for all eligible salaried employees. Entity Voluntary Filers Employee Benefit Plan [Member] Employee benefit plan Represents information pertaining to employee benefit plan in effect for certain non-union hourly employees. Entity Current Reporting Status Defined Contribution Plans [Line Items] Defined contribution plan Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Entity Filer Category National Electrical Annuity Plan [Member] National Electrical Annuity Plan Represents information pertaining to national electrical annuity plan. Entity Public Float Eighth District Electrical Pension Fund Annuity Plan [Member] Eighth District Electrical Pension Fund Annuity Plan Represents information pertaining to eighth district electrical pension fund annuity plan. Entity Registrant Name National Electrical Benefit Fund [Member] National Electrical Benefit Fund Represents information pertaining to national electrical pension fund. Entity Central Index Key Eighth District Electrical Pension Fund [Member] Eighth District Electrical Pension Fund Represents information pertaining to eighth district electrical pension fund. IBEW Local 1249 Pension Plan [Member] IBEW Local 1249 Pension Plan Represents information pertaining to IBEW Local 1249 Pension Plan. Number of Locals Covered under Multiemployer Defined Plans Number of local unions Represents information pertaining to number of locals covered under multiemployer defined plan. Multiemployer Plans, Red Zone Funded Status, Percentage Percentage funded for red zone Represents the percentage funded for red zone status. Entity Common Stock, Shares Outstanding Multiemployer Plans, Yellow Zone Funded Status, Percentage Percentage funded for yellow zone Represents the percentage funded for yellow zone status. Multiemployer Plans, Green Zone Funded Status, Percentage Percentage funded for green zone Represents the percentage funded for green zone status. Minimum Extended Period of Contracting Cycle for Long Term Contracts Minimum extended period of contracting cycle for long-term contracts Represents the minimum extended period of contracting cycle for certain long-term contracts. Minimum Extended Period for Collection of Retainage on Certain Long Term Contracts Minimum extended period for collection of retainage on certain long-term contracts Represents the minimum extended period for collection of retainage on certain long-term contracts. Number of Customers Individually Exceeding 10 Percent of Consolidated Contract Revenue Number of customers individually exceeding 10.0% of consolidated contract revenue Represents the number of customers individually exceeding 10 percent of consolidated contract revenue. Percentage of Retainage Recorded and Collected Percentage of retainage recorded and expected to be collected within one year Represents the percentage of retainage of long-term contracts recorded and expected to be collected by the entity within one year. Real Estate Lease Term Real estate lease term Represents the real estate maximum lease term. Debt Instrument, Covenant Leveraged Debt Ratio Leveraged debt ratio Represents the maximum leveraged debt ratio under the credit agreement. Debt Instrument, Covenant Interest Coverage Ratio Interest coverage ratio Represent the minimum interest coverage ratio under the credit agreement. Volatility Period over which Common Stock Publicly Traded Volatility period over which the entity's common stock was traded Represents the volatility period over which the entity's common stock was publicly traded prior to grants. Schedule of Segment Reporting Information Related to Allocation of Depreciation and Amortization by Segment [Table Text Block] Schedule of an allocation of total depreciation, including depreciation of shared construction equipment, and amortization Tabular disclosure of total depreciation and amortization for each reportable segment. Accrued Payroll and Incentive Compensation, Current Payroll and incentive compensation Carrying value as of the balance sheet date of the obligations incurred through that date and payable for employees' services provided, including obligations incurred and payable for incentive compensation awarded to employees. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Accrued Union Dues and Benefits Union dues and benefits Carrying value as of the balance sheet date of the obligations incurred through that date and payable for union dues and benefits. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Outstanding Performance Bonds Aggregate original face amount of outstanding bonds issued by the surety The total amount of outstanding performance bonds. Estimated Cost to Complete Bonded Projects Estimated remaining cost to complete bonded projects Estimated cost to complete bonded projects. Multiemployer Plans Minimum Contribution as Percent of Wages Minimum future contributions (as a percent) Amount of minimum contribution(s) as a percent of wages required for future periods to a multiemployer plan by collective bargaining arrangements, statutory obligations, or other contractual obligations. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. Cost Estimate Revision Gross Margin Increase Percentage Gross margin increased as a result of change in estimates pertaining to large transmission projects (as a percent) Increase in gross margin percentage recognized as a result of revised cost estimates. Document Fiscal Year Focus LE Myers Co [Member] L.E. Myers Co Represents information pertaining to L.E. Myers Co. Document Fiscal Period Focus Vehicular Traffic Accident Case [Member] Vehicular traffic accident Represents the information pertaining to vehicular traffic accident case. Loss Contingency Punitive Damages Awarded Value Punitive damages Represents the amount of the proposed punitive damage awards issued in a legal judgment. Loss Contingency Maximum Multiple of Compensatory Damages for Estimated Punitive Damages that Can be Sought Maximum number of times of compensatory damages for estimated punitive damages Represents the maximum multiple of compensatory damages the entity believes is supported by Florida law. Number of Construction Equipment Leases Entered Number of new construction equipment leases entered Represents the number of new construction equipment leases entered into during the period. Finite Lived Intangible Asset Residual Value Residual value Represents the aggregate expected value at the end of their useful life of a major finite-lived intangible asset class during the period. Number of Operating Leases Number of leases that included guaranteed residual values Represents number of leases that included guaranteed residual values. Legal Settlement Liabilities Current Legal settlements Represents the carrying value as of the balance sheet date of potential legal settlement obligations, the payment of which are uncertain. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer). Range of Exercise Prices from Dollars 18.01 to 24.68 [Member] Exercise Price Ranges, $18.01-$24.68 Represents the range of exercise price from 18.01 dollars per share to 24.68 dollars per share. Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Grants at Target In Period Granted at target (in shares) Represents the number of grants made at target during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Represents the weighted average fair value at grant date for nonvested equity-based awards issued at target during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Grants at Target In Period Weighted Average Grant Date Fair Value Granted at target (in dollars per share) Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Forfeited for Performance Below Target in Period Forfeited for performance below target (in shares) Represents the number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited for performance below target during the reporting period. Legal Entity [Axis] ASU No. 2011-04 Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Forfeitures for Performance Below Target Weighted Average Grant Date Fair Value Forfeited for performance below target (in dollars per share) Represents the weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event for performance below target. Document Type Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Earned for Performance Above Target In Period Earned for performance above target (in shares) Represents the number of equity-based payment instruments other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan) earned for performance above target during the period. Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Earned For Performance Above Target in Period Weighted Average Grant Date Fair Value Represents the weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were earned for performance above target during the period. Earned for performance above target (in dollars per share) Represents information pertaining to Northern States Power Company (Wisconsin) v. The City of Ashland, Wisconsin. Northern States Power Company Wisconsin Vs The City of Ashland Wisconsin [Member] Northern States Power Company (Wisconsin) v. The City of Ashland, Wisconsin Period During which Defendant Operated Manufactured Gas Plant Period during which the defendant operated a manufactured gas plant Represents the period during which the defendant operated a manufactured gas plant. Use of Estimates [Abstract] Use of Estimates Share Based Compensation Arrangement by Share Based Payment Award Number of Performance Measures Number of performance measures Represents the number of performance measures under share-based compensation plans. Performance Period [Axis] Information by performance period pertaining to equity-based compensation. Proceeds from Issuance of Shares and Payments Related to Tax Withholding for Share-based Compensation under Incentive and Share-based Compensation Plans Including Stock Options Employee stock option and restricted stock transactions Amount of cash inflow associated with the amount received from holders to acquire the entity's shares under incentive and share awards, including stock option exercises, and the amount of cash outflow to satisfy an employee's income tax withholding obligation as part of a net-share settlement of a share-based award. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately. Represents the amount of decrease in additional paid in capital (APIC) resulting from direct costs associated with the repurchase of stock. Adjustments to Additional Paid in Capital Under Stock Repurchased Costs Total cost recorded as reduction of additional paid-in capital under Repurchase Program Share Repurchase Program [Abstract] Share Repurchase Program Accrued Liabilities Accounts Payable and Accrued Liabilities Disclosure [Text Block] Accounts receivable, net of allowances of $1,168 and $1,132, respectively Accounts receivable, net current Accounts Receivable, Net, Current Accounts receivable, gross current Accounts Receivable, Gross, Current Accounts payable Accounts Payable, Current Accounts Receivable Accounts, Notes, Loans and Financing Receivable, Net, Current [Abstract] Accounts receivable Accounts Receivable [Member] Accounts Receivable and Allowance for Doubtful Accounts Accounts Receivable, Net [Abstract] Taxes, other than income taxes Accrual for Taxes Other than Income Taxes, Current Payroll and incentive compensation Accrued Income Taxes, Current Accrued income taxes Property and equipment, accumulated depreciation (in dollars) Less: Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Additional paid-in capital Additional Paid in Capital, Common Stock Additional Paid-In Capital Additional Paid-in Capital [Member] Tax benefit from stock-based awards Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Adjustments to reconcile net income to net cash flows provided by operating activities - Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Stock-based compensation expense Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Advertising costs Advertising Expense Advertising Advertising Costs, Policy [Policy Text Block] Stock-based compensation expense recognized Allocated Share-based Compensation Expense Accounts receivable, allowances (in dollars) Less: Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Roll-forward activity of allowance for doubtful accounts Allowance for Doubtful Accounts Receivable [Roll Forward] Write offs, net of recoveries Allowance for Doubtful Accounts Receivable, Write-offs Balance at beginning of period Balance at end of period Allowance for Doubtful Accounts Receivable Amortization of intangible assets Amortization expense Amortization of Intangible Assets Antidilutive Securities [Axis] Earnings Per Share Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities, Name [Domain] Shares of common stock excluded from the calculation of dilutive securities Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Total assets Assets Assets Current assets: Assets, Current [Abstract] ASSETS Assets [Abstract] Total current assets Assets, Current Billings in excess of costs and estimated earnings on uncompleted contracts Billings in excess of costs and estimated earnings on uncompleted contracts Billings in Excess of Cost, Current Contracts in Process Acquisition of property and equipment for which payment is pending Capital Expenditures Incurred but Not yet Paid Cash and cash equivalents: Cash and Cash Equivalents, at Carrying Value [Abstract] Cash and cash equivalents Beginning of period End of period Cash and Cash Equivalents, at Carrying Value Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] Supplemental Cash Flows Cash Flow, Supplemental Disclosures [Text Block] Use of Estimates Change in Accounting Estimate [Line Items] Change in Accounting Estimate, Type [Domain] Change in Accounting Estimate by Type [Axis] Commitments and Contingencies Commitments Contingencies and Guarantees [Text Block] Commitments and Contingencies Commitments and contingencies Commitments and Contingencies. Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common Stock Common Stock [Member] Common stock, issued shares Common Stock, Shares, Issued Balance (in shares) Balance (in shares) Common stock-$0.01 par value per share; 100,000,000 authorized shares; 21,322,196 and 21,223,076 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively Common Stock, Value, Outstanding Common stock, authorized shares Common Stock, Shares Authorized Common stock, outstanding shares Beginning balances (in shares) Ending balances (in shares) Common Stock, Shares, Outstanding Employee Benefit Plans Concentration Risk Type [Domain] Concentrations Concentration Risk [Line Items] Concentration Risk Benchmark [Domain] Concentrations Concentration Risk, Credit Risk, Policy [Policy Text Block] Concentration Risk Type [Axis] Concentration Risk [Table] Concentration Risk Benchmark [Axis] Percentage of concentration risk Concentration Risk, Percentage Consolidation Items [Domain] Consolidation Consolidation, Policy [Policy Text Block] Consolidation Items [Axis] Classification of Construction Contract-related Assets and Liabilities Construction Contractors, Policy [Policy Text Block] Contract retainages Contract Receivable Retainage, Due in Next Twelve Months Contract receivables Contract Receivable, Due in Next Twelve Months Contracts in process Contracts Accounted for under Percentage of Completion [Member] Other Corporate Segment [Member] General Corporate Corporate, Non-Segment [Member] Contract costs Cost of Services Net asset (liability) position for contracts in process included in consolidated balance sheets Costs in Excess of Billings on Uncompleted Contracts or Programs [Abstract] Costs and estimated earnings in excess of billings on uncompleted contracts Costs in Excess of Billings, Current Concentrations of credit risk Credit Concentration Risk [Member] State Current State and Local Tax Expense (Benefit) Current Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) Current income tax expense (benefit), Total Current Income Tax Expense (Benefit) Customer relationships Customer Relationships [Member] Customer concentration risk Customer Concentration Risk [Member] Variable rate basis Debt Instrument, Description of Variable Rate Basis Debt and Borrowing Arrangements Debt Instrument [Line Items] Schedule of Long-term Debt Instruments [Table] Interest rate margin (as a percent) Debt Instrument, Basis Spread on Variable Rate Debt and Borrowing Arrangements Debt and Borrowing Arrangements Debt Disclosure [Text Block] Term of the credit agreement Debt Instrument, Term Debt Instrument [Axis] Debt Instrument, Name [Domain] Deferred income tax liabilities: Deferred Tax Liabilities, Net [Abstract] Total deferred income tax liabilities Deferred Tax Liabilities, Gross Federal Deferred Federal Income Tax Expense (Benefit) Deferred Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Deferred income taxes Deferred income tax expense (benefit), Total Deferred Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Stock-based awards Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Bonus Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Bonuses Balance sheet classification of deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Classification [Abstract] Other Deferred Tax Assets, Other Deferred income tax assets Current deferred income tax assets Deferred Tax Assets, Net of Valuation Allowance, Current Total deferred income tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred income tax assets: Deferred Tax Assets, Net [Abstract] Deferred income tax liabilities Non-current deferred income tax liabilities Deferred Tax Liabilities, Net, Noncurrent Property and equipment-tax over book depreciation Deferred Tax Liabilities, Property, Plant and Equipment Intangible assets-tax over book amortization Deferred Tax Liabilities, Intangible Assets Net deferred income taxes Deferred Tax Liabilities, Net Self insurance reserves Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Self Insurance Contract loss reserves Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Loss Reserves Contributions Defined Contribution Plan, Cost Recognized Depreciation and amortization of property and equipment Depreciation and amortization expense Depreciation Depreciation and amortization Depreciation, Depletion and Amortization Eligible members of the Board of Directors Director [Member] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-Based Compensation Earnings per share Earnings Per Share, Basic and Diluted [Abstract] Earnings Per Share Earnings Per Share [Text Block] Earnings Per Share Earnings Per Share, Policy [Policy Text Block] -Basic (in dollars per share) Income per common share, basic (in dollars per share) Earnings Per Share, Basic Basic earnings per share (in dollars per share) -Diluted (in dollars per share) Income per common share, diluted (in dollars per share) Earnings Per Share, Diluted Income per common share: Earnings Per Share Domestic production/manufacturing deduction (as a percent) Effective Income Tax Rate Reconciliation, Deduction, Qualified Production Activity, Percent Total (as a percent) Effective Income Tax Rate Reconciliation, Percent Differences between the U.S. federal statutory rate and the Company's effective tax rate for continuing operations Effective Income Tax Rate Reconciliation, Percent [Abstract] State income taxes, net of U.S. federal income tax expense (as a percent) Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent Other, net (as a percent) Effective Income Tax Rate Reconciliation, Other Adjustments, Percent Deferred tax adjustments, net (as a percent) Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Percent U.S. federal statutory tax rate (as a percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Non-deductible meals and entertainment (as a percent) Effective Income Tax Rate Reconciliation, Nondeductible Expense, Meals and Entertainment, Percent Research and development credit (as a percent) Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent Refund of fine related to OSHA violation (as a percent) Effective Income Tax Rate Reconciliation, Tax Settlement, Percent Other information Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Stock options Employee Stock Option [Member] Total unrecognized stock-based compensation expense, net of estimated forfeitures Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted average vesting period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Equity Component [Domain] Excess tax benefit from stock-based awards Excess Tax Benefit from Share-based Compensation, Financing Activities Fair Value Measurements Fair Value Measurements Fair Value Disclosures [Text Block] Estimated useful life Finite-Lived Intangible Asset, Useful Life Gross carrying amount of finite-lived intangible assets Finite-Lived Intangible Assets, Gross 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Five 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Three Intangible asset amortization expense Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Intangible assets, accumulated amortization (in dollars) Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets by Major Class [Axis] Remaining amortization period Finite-Lived Intangible Assets, Remaining Amortization Period 2014 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2017 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2015 Finite-Lived Intangible Assets, Amortization Expense, Year Two Gain on sale of property and equipment Gain (Loss) on Disposition of Property Plant Equipment Impairment charges Goodwill and Intangible Asset Impairment Goodwill and Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Goodwill and Intangible Assets Goodwill and Intangible Asset Impairment [Abstract] Goodwill Gross carrying amount of goodwill Goodwill Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Goodwill and Intangible Assets Gross profit Gross profit Gross Profit CONSOLIDATED STATEMENTS OF OPERATIONS Income before provision for income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest Income from operations Income Taxes Unrecognized tax benefits Income Tax Contingency [Line Items] Income Taxes Income Tax Disclosure [Text Block] Income Tax Contingency [Table] Income tax expense Income tax expense Income Tax Expense (Benefit) Income taxes Income Taxes Paid Refundable income taxes Income Taxes Receivable, Current Income Taxes Income Tax, Policy [Policy Text Block] Accounts receivable, net Increase (Decrease) in Accounts Receivable Accounts payable Increase (Decrease) in Accounts Payable Accrued self insurance Increase (Decrease) in Self Insurance Reserve Billings in excess of costs and estimated earnings on uncompleted contracts Increase (Decrease) in Billing in Excess of Cost of Earnings Other liabilities Increase (Decrease) in Other Operating Liabilities Changes in operating assets and liabilities Increase (Decrease) in Operating Capital [Abstract] Construction materials inventory Increase (Decrease) in Inventories Receivable for insurance claims in excess of deductibles Increase (Decrease) in Insurance Settlements Receivable Other assets Increase (Decrease) in Other Operating Assets Costs and estimated earnings in excess of billings on uncompleted contracts Increase (Decrease) in Unbilled Receivables Increase (Decrease) in Stockholders Equity Changes in outstanding shares of common stock Increase (Decrease) in Stockholders' Equity [Roll Forward] Indefinite-lived intangible trademarks Indefinite-lived intangible tradenames Indefinite-Lived Trade Names Receivable for insurance claims in excess of deductibles Insurance Settlements Receivable Insurance and Claims Accruals Insurance Claims [Member] Intangible assets, net of accumulated amortization of $3,060 and $2,893, respectively Intangible Assets, Net (Excluding Goodwill) Net carrying amount of goodwill and other intangible assets Intangible Assets, Net (Including 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STOCKHOLDERS' EQUITY Liabilities and Equity [Abstract] Commitment fee on unused portion of facility (as a percent) Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Interest rate (as a percent) Line of Credit Facility, Interest Rate at Period End Remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Litigation Case [Domain] Litigation Case [Axis] Accounts Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Contracts in Process Long-term Contracts or Programs Disclosure [Text Block] Net payments made Loss Contingency Accrual, Payments Loss Contingency, Nature [Domain] Loss Contingencies [Table] Net increases in reserves Loss Contingency Accrual, Provision Roll forward of activity in the insurance reserves Loss Contingency Accrual [Roll Forward] Damages alleged Loss Contingency, Damages Sought, Value Commitments and Contingencies Loss 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Operations Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Net income Net income Net income Net Income (Loss) Attributable to Parent Amount of effect on the company's financial position, results of operations or cash flows due to adoption of ASU Recently Issued and Adopted Accounting Pronouncements Recent Accounting Pronouncements Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Noncash investing activities: Noncash Investing and Financing Items [Abstract] Acquisition of property and equipment through like-kind exchange of similar assets Noncash or Part Noncash Acquisition, Fixed Assets Acquired Other income (expense) Nonoperating Income (Expense) [Abstract] Number of business segments Number of reporting segments Number of Reportable Segments Office equipment Office Equipment [Member] Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Future minimum 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Noncurrent Other current assets Other Assets, Current Other Other Receivables, Gross, Current Other current liabilities Other Liabilities, Current [Abstract] Other non-cash items Other Noncash Expense Other, net Other Nonoperating Income (Expense) Other liabilities Other Liabilities, Noncurrent Other current liabilities Other current liabilities, total Other Liabilities, Current Profit sharing and thrift plan Other Employee Related Liabilities, Current Other Other Accrued Liabilities, Current Prime Rate Prime Rate [Member] Less: Net income allocated to participating securities Participating Securities, Distributed and Undistributed Earnings Accrued Liabilities Repurchase of common shares Payments for Repurchase of Common Stock Legal expenses paid Payments for Legal Settlements Cash paid for acquired business Payments to Acquire Businesses, Gross Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Debt issuance costs Payments of Debt Issuance Costs Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Performance Awards Performance awards Performance Shares [Member] Plan Name [Domain] Plan Name [Axis] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock-$0.01 par value per share; 4,000,000 authorized shares; none issued and outstanding at June 30, 2014 and December 31, 2013 Preferred Stock, Value, Outstanding Preferred stock, issued shares Preferred Stock, Shares Issued Preferred stock, authorized shares Preferred Stock, Shares Authorized Preferred stock, outstanding shares Preferred Stock, Shares Outstanding Preferred Stock Preferred Stock [Member] Reclassification Reclassification, Policy [Policy Text Block] Other financing activities Proceeds from (Payments for) Other Financing Activities Net borrowings on revolving credit facility Proceeds from (Repayments of) Lines of Credit Proceeds from exercise of stock options Proceeds from Issuance of Common Stock Proceeds from exercise of stock options Proceeds from Stock Options Exercised Proceeds from sale of property and equipment Proceeds from Sale of Property, Plant, and Equipment Employee stock option and restricted stock transactions Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Estimated useful lives Estimated Useful Life Property, Plant and Equipment, Useful Life Property and equipment, gross Property, Plant and Equipment, Gross Property and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Property and equipment, net of accumulated depreciation of $131,506 and $115,679, respectively Property and equipment, net Property, Plant and Equipment, Net Property and Equipment Schedule of property and equipment Property, Plant and Equipment [Table Text Block] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Axis] Property and Equipment Property, Plant and Equipment Disclosure [Text Block] Property and Equipment Property, Plant and Equipment [Line Items] Reduction in (provision for) allowances Provision for Doubtful Accounts Outstanding purchase orders for certain construction equipment Purchase Commitment, Remaining Minimum Amount Committed Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Quarterly Financial Data (Unaudited) Range [Axis] Range [Domain] Accounts Receivable Reconciliation of Assets from Segment to Consolidated [Table] Reconciliation of the beginning and ending liabilities for unrecognized tax benefits Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Schedule of identifiable assets for each segment Reconciliation of Assets from Segment to Consolidated [Table Text Block] Payments of capital lease obligations Repayments of Long-term Capital Lease Obligations Repayments on term loan Repayments of Long-term Debt Adjustment Restatement Adjustment [Member] Restricted stock Restricted Stock [Member] Retained Earnings Retained Earnings [Member] Retained earnings Retained Earnings (Accumulated Deficit) Revenue Recognition Revenue Recognition [Abstract] Revenue Recognition Revenue Recognition, Policy [Policy Text Block] Revolving credit facility Revolving Credit Facility [Member] Weighted-Average Exercise Price (in dollars per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price Exercisable at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Expected term Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Weighted-Average Exercise Price (in dollars per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price Exercisable at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Outstanding at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Weighted-Average Remaining Contractual Term Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term Revenues Sales [Member] Contract revenues Revenues Sales Revenue, Services, Net Scenario, Unspecified [Domain] Schedule of Multiemployer Plans [Table] Schedule of Common Stock Outstanding Roll Forward [Table Text Block] Schedule of changes in outstanding shares of common stock Schedule of shares of common stock underlying the Company's unvested stock options and performance awards excluded from the calculation of dilutive securities Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of the stock option activity Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Nonvested Performance-based Units Activity [Table Text Block] Summary of performance shares activity Schedule of supplemental disclosures of cash flow information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of the fair value and assumptions used in determining the fair value of stock options granted Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Schedule of income tax provision from continuing operations Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of goodwill and intangible assets Schedule of Intangible Assets and Goodwill [Table Text Block] Schedule of differences between the U.S. federal statutory tax rate and the Company's effective tax rate for continuing operations Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Schedule of net deferred tax assets and (liabilities) Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Schedule of reconciliation of the beginning and ending liabilities for unrecognized tax benefits Schedule of restricted stock activity Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Schedule of Accrued Liabilities [Table Text Block] Schedule of other current liabilities Schedule of Change in Accounting Estimate [Table] Schedule of Quarterly Financial Information [Table Text Block] Schedule of unaudited consolidated operating results by quarter Net income available to common shareholders and the weighted average number of common shares used to compute basic and diluted 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Exercise Price Range, Number of Exercisable Options Exercise price, high end of range (in dollars per share) Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit Shares received as payment for withholding taxes due by holders of awards Shares Paid for Tax Withholding for Share Based Compensation Outstanding amount of credit agreement Short-term Debt Estimated reduction in unrecognized tax benefit due to the lapses in the applicable statutes of limitations and pending federal tax settlements Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecorded Benefit Standby letter of credit Standby Letters of Credit [Member] Scenario [Axis] Statement [Table] Statement Stockholders' Equity Statement [Line Items] CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY CONSOLIDATED STATEMENTS OF CASH FLOWS Equity Components [Axis] CONSOLIDATED BALANCE SHEETS Segments [Axis] Stock Issued During Period, Shares, Period 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available for further repurchases Stock Repurchase Program, Remaining Authorized Repurchase Amount Stockholders' equity: Stockholders' Equity Attributable to Parent [Abstract] Stockholders' Equity, Period Increase (Decrease) Total stockholders' equity Balance Balance Stockholders' Equity Attributable to Parent Stockholders' Equity Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Subsidiary Supplemental Cash Flows Performance and Payment Bonds Surety Bond [Member] Title of Individual [Axis] Relationship to Entity [Domain] Accounts Receivable and Allowance for Doubtful Accounts Trade and Other Accounts Receivable, Policy [Policy Text Block] Treasury stock, shares Treasury Stock, Shares Weighted-average price (in dollars per share) Treasury Stock Acquired, Average Cost Per Share Treasury stock, at cost - 3,310 and 0 shares, respectively Treasury Stock, Value Interest and penalties charged to income tax expense as a result of the unrecognized tax benefits Unrecognized 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