Treasury Stock, Value Treasury stock, 11,256,218 and 2,843,324 common shares, at cost Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of period Cash and cash equivalents, beginning of period Cash and cash equivalents Costs and estimated earnings in excess of billings on uncompleted contracts Inventory, Net Inventories Assets, Current Total current assets Property, Plant and Equipment, Net Property, Plant and Equipment, Net, Ending Balance Property, Plant and Equipment, Net, Beginning Balance Property, Plant and Equipment, Net, Total Property and equipment, net of accumulated depreciation of $501,235 and $428,025 Other assets, net Intangible Assets, Net (Excluding Goodwill) Intangible assets, net Intangible Assets, Net (Excluding Goodwill), Total Other intangible assets, net of accumulated amortization of $155,678 and $134,735 Assets Total assets Goodwill Goodwill, Ending Balance Goodwill, Beginning Balance Goodwill, net Goodwill Billings in Excess of Cost Billings in excess of costs and estimated earnings on uncompleted contracts Liabilities, Current Total current liabilities Deferred Tax Liabilities, Noncurrent Deferred income taxes Other Liabilities, Noncurrent Insurance and other non-current liabilities Liabilities Total liabilities Common Stock, Value, Issued Common stock, value Retained Earnings(Accumulated Deficit) Retained earnings Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Stockholders' Equity Attributable to Parent Total stockholders' equity Stockholders' Equity Attributable to Noncontrolling Interest Carrying value of the investment held by noncontrolling interest in variable interest entities Noncontrolling interests Liabilities and Stockholders' Equity Total liabilities and equity ASSETS Current Assets: LIABILITIES AND EQUITY Current Liabilities: Equity: Per Share Information [Abstract] Earnings per share attributable to common stock: Document and Entity Information [Abstract] Document and Entity Information. Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] BUSINESS AND ORGANIZATION Goodwill and Intangible Assets Disclosure [Text Block] GOODWILL AND OTHER INTANGIBLE ASSETS Debt Disclosure [Text Block] DEBT OBLIGATIONS Stockholders' Equity Note Disclosure [Text Block] EQUITY Segment Reporting Disclosure [Text Block] SEGMENT INFORMATION Commitments and Contingencies Disclosure [Text Block] COMMITMENTS AND CONTINGENCIES Cash Flows from Financing Activities: Cash Flows from Investing Activities: Cash Flows from Operating Activities: Changes in operating assets and liabilities, net of non-cash transactions - (Increase) decrease in - Increase (decrease) in - Gross Profit Gross profit Gross profit Selling, General and Administrative Expense Selling, general and administrative expenses Selling, General and Administrative Expense, Total Selling, general and administrative expenses Amortization of Intangible Assets Amortization Expense Total amortization expense Amortization of Intangible Assets, Total Amortization of intangible assets Total amortization expense Interest Expense Interest expense Interest expense Interest income Other Nonoperating Income (Expense) Other income (expense), net Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Cumulative Effects of Changes in Accounting Principles, Noncontrolling Interest Income before income taxes Income Tax Expense (Benefit) Provision for income taxes Net Income (Loss) Available to Common Stockholders, Basic Net income attributable to common stock Net income attributable to common stock Earnings Per Share, Basic Basic Earnings Per Share, Basic, Total Basic earnings per share Earnings Per Share, Diluted Diluted Earnings Per Share, Diluted, Total Diluted earnings per share Weighted Average Number of Shares Outstanding, Basic Weighted average shares outstanding for basic earnings per share Weighted average basic shares outstanding Weighted Average Number of Shares Outstanding Weighted average shares outstanding for diluted earnings per share Weighted average diluted shares outstanding Depreciation Depreciation Amortization of debt issuance costs Recognition of Deferred Revenue Amortization of deferred revenues (Gain)/loss on sale of property and equipment Gain (Loss) on Sale of Property Plant Equipment (Gain) loss on sale of property and equipment Provision for Doubtful Accounts Provision for (recovery of) doubtful accounts Deferred Income Tax Expense (Benefit) Deferred income tax (benefit) provision Share-based Compensation Total stock-based compensation included in selling, general and administrative expenses Non-cash stock-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Tax impact of stock-based equity awards Increase (Decrease) in Accounts and Notes Receivable Accounts and notes receivable Increase (Decrease) in Unbilled Receivables Costs and estimated earnings in excess of billings on uncompleted contracts Increase (Decrease) in Inventories Inventories Billings in excess of costs and estimated earnings on uncompleted contracts Net Cash Provided by (Used in) Operating Activities Net cash provided by (Used in) operating activities Proceeds from Sale of Property, Plant, and Equipment Proceeds from sale of property and equipment Payments to Acquire Property, Plant, and Equipment Additions of property and equipment Net cash used in investing activities Proceeds from other long-term debt Repayments of Other Long-term Debt Payments on other long-term debt Tax impact of stock-based equity awards Proceeds from Stock Options Exercised Exercise of stock options Net cash used in financing activities Cash and Cash Equivalents, Period Increase (Decrease) Net decrease in cash and cash equivalents Effect of Exchange Rate on Cash and Cash Equivalents Effect of foreign exchange rate changes on cash and cash equivalents Common stock, par value Common stock, shares authorized Common Stock, Shares, Issued Common Stock, Shares, Issued, Total Common stock, shares issued Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common Stock outstanding Common stock, shares outstanding Treasury stock, common shares Allowance for Doubtful Accounts Receivable, Current Allowances for doubtful accounts, Current Allowances on accounts receivable Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Accumulated depreciation on property and equipment Finite-Lived Intangible Assets, Accumulated Amortization Accumulated Amortization Accumulated amortization on other intangible assets Total accumulated amortization Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total equity Net income Accounts Payable and Accrued Liabilities, Current Accounts payable and accrued expenses Accounts Receivable, Net, Current Accounts Receivable, Net, Current, Total Accounts receivable, net of allowances of $6,317 and $6,105 Net Income (Loss) Attributable to Noncontrolling Interest Less: Net income attributable to noncontrolling interests Reduction in net income as a result of non controlling interest distribution Net income Supplemental disclosure of cash flow information: Proceeds from Income Tax Refunds Income tax refunds Cash paid received during the period for [Abstract] Cash (paid) received during the period for - Cash (paid) received during the period for. Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net income to net cash provided by (used in) operating activities - Non-cash interest expense Increase (Decrease) in Other Operating Liabilities Other, net Interest Paid Interest paid Interest paid Interest paid Income Taxes Paid Income taxes paid Income taxes paid Income taxes paid Cost of Services Cost of services (including depreciation) Other Assets, Current Prepaid expenses and other current assets Additional Paid in Capital, Common Stock Additional paid-in capital Increase (Decrease) in Prepaid, Deferred Expense and Other Assets Prepaid expenses and other current assets Accounts payable and accrued expenses and other non-current liabilities Earnings Per Share [Text Block] PER SHARE INFORMATION Earnings per share attributable to common stock: Significant Accounting Policies [Text Block] SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Net Cash Provided by (Used in) Financing Activities Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Current Reporting Status Entity Filer Category Statement [Table] Statement [Line Items] Assets [Abstract] Assets, Current [Abstract] Costs in Excess of Billings on Uncompleted Contracts or Programs Expected to be Collected within One Year Other Assets, Noncurrent Liabilities and Stockholders' Equity [Abstract] Liabilities, Current [Abstract] Stockholders' Equity Attributable to Parent [Abstract] Common Stock, Par or Stated Value Per Share Common Stock, Shares Authorized Treasury Stock, Shares Investment Income, Interest Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net Cash Provided by (Used in) Operating Activities [Abstract] Amortization of Debt Discount (Premium) Amortization of Financing Costs Increase (Decrease) in Operating Capital [Abstract] Increase (Decrease) in Operating Assets [Abstract] Increase (Decrease) in Operating Liabilities [Abstract] Increase (Decrease) in Other Accounts Payable and Accrued Liabilities Increase (Decrease) in Billing in Excess of Cost of Earnings Net Cash Provided by (Used in) Investing Activities [Abstract] Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from Issuance of Other Long-term Debt Excess Tax Benefit from Share-based Compensation, Financing Activities Supplemental Cash Flow Information [Abstract] Condensed Consolidated Balance Sheets [Abstract] Condensed Consolidated Statements of Operations [Abstract] New Accounting Pronouncements [Abstract] Condensed Consolidated Statements of Cash Flows [Abstract] Equity [Abstract] Disclosure of Compensation Related Costs, Share-based Payments [Text Block] LONG-TERM INCENTIVE PLANS Foreign Currency Transaction Gain (Loss), Unrealized Foreign currency (gain) loss Foreign currency (gain) loss Business and Organization (Textual) [Abstract] Business and Organization (Textual) [Abstract] Business and organization. Business Acquisition, Cost of Acquired Entity, Cash Paid Cash paid Cash paid for acquisition Cash Equivalents, at Carrying Value Cash equivalents Cash and cash equivalents held in domestic bank accounts Cash and cash equivalents held in domestic bank accounts Cash and cash equivalents held in domestic bank accounts. Cash and cash equivalents held in foreign bank accounts Cash and cash equivalents held in foreign bank accounts Cash and cash equivalents held in foreign bank accounts. Unrecognized Tax Benefits Unrecognized tax benefits related to uncertain tax positions Deferred Revenue, Noncurrent Fiber optic non-current deferred revenue Unrecognized Tax Benefits, Period Increase (Decrease) Increase (decrease) in unrecognized tax benefits related to uncertain tax positions from last fiscal year Contract Receivable Retainage, Due One Year or Less Current retainage balances Unbilled receivables Unbilled Contracts Receivable Contract Receivable Retainage, Due after One Year Non-current retainage balances Interest expense (income) and penalties Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense Business Acquisition, Cost of Acquired Entity, Equity Interests Issued and Issuable Value of Quanta common stock issued Common stock value Document Fiscal Year Focus Document Fiscal Period Focus Minimum future licensing revenues. Minimum future licensing revenues [Abstract] Minimum Future Licensing Revenues (In thousands) Minimum future licensing revenues thereafter Minimum future licensing revenues, thereafter. Thereafter Minimum future licensing revenues Minimum future licensing revenues, total. Fixed non-cancelable minimum licensing revenues Shares used in computing earnings per share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Summary of changes in Quanta's goodwill Schedule of Goodwill [Text Block] Estimated future aggregate amortization expense of intangible assets Finite-Lived Intangible Assets, Future Amortization Expense [Abstract] Electric Power Division [Member] Electric power division. Natural Gas and Pipeline Division [Member] Natural gas and pipeline division. Telecommunications Division [Member] Telecommunications division. Customer relationships [Member] Backlog [Member] Non-compete agreements [Member] Patented rights and developed technology [Member] Goodwill and Other Intangible Assets (Textual) [Abstract] Goodwill and other intangible assets. Goodwill and Other Intangible Assets (Textual) [Abstract] Debt Instrument, Interest Rate, Stated Percentage Annual interest rate of convertible subordinated notes Other intangible assets Schedule of Finite-Lived Intangible Assets by Major Class [Text Block] Finite-Lived Intangible Assets, Gross Finite-Lived Intangible Assets, Gross, Total Intangible assets Finite-Lived Intangible Assets, Average Useful Life Remaining weighted average amortization periods in years Expenses for the amortization of intangible assets Finite-Lived Intangible Assets, Amortization Expense Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Convertible Subordinated Debt [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Changes in Accounting Principles and New Accounting Pronouncements (Textual) Summary of changes in Quanta's goodwill Goodwill [Roll Forward] Other intangible assets Finite-Lived Intangible Assets, Net [Abstract] Future amortization expense remainder of current period 2011 (Remainder) Future amortization expense remainder of current period. Net income attributable to common stock for diluted earnings per share Net Income (Loss) Available to Common Stockholders, Diluted WEIGHTED AVERAGE SHARES: Basic and diluted earnings per share Earnings Per Share Reconciliation [Abstract] Per Share Information (Textual) [Abstract] Per Share Information (Textual) [Abstract] Per share information. Debt Obligations (Textual) [Abstract] Debt Obligations (Textual) [Abstract] Debt obligations. Reduction in Company Maximum Funded Debt and Maximum Senior Debt by all Cash and Cash Equivalents in Excess of Amount Reduction in Quanta's maximum funded debt and maximum senior debt by all cash and cash equivalents in excess of amount Reduction in Quanta's maximum funded debt and maximum senior debt by all cash and cash equivalents in excess of amount. Senior secured revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Expiration Date Maturity date of senior secured revolving credit facility Line of Credit Facility, Amount Outstanding Letters of credit issued under credit facility Line of Credit Facility, Remaining Borrowing Capacity Credit facility available for revolving loans or issuing new letters of credit Effect of dilutive stock options Incremental Common Shares Attributable to Share-based Payment Arrangements, Total Incremental Common Shares Attributable to Share-based Payment Arrangements Non-cash compensation expense related to restricted stock Restricted Stock Expense Stock Option Plan Expense Non-cash compensation expense related to stock options Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Income tax benefit related to non-cash compensation expense Non Cash Compensation Expense and Related Tax Benefits [Abstract] Non cash compensation expense and related tax benefits. Non-cash compensation expense and related tax benefits Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Grant of restricted stocks under the Plans Weighted average grant price Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Restricted stock, vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Fair value of additional restricted stock, vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value Restricted Stock [Member] Change orders and/or claims Unapproved Change Orders, Amount Comprehensive Income, Net of Tax, Attributable to Parent [Abstract] Comprehensive Income Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax Other Comprehensive Income, Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total Foreign currency translation adjustment, net of tax Other Comprehensive Income, Derivatives Qualifying as Hedges, Net of Tax Change in unrealized gain (loss) on foreign currency cash flow hedges, net of tax Comprehensive Income, Net of Tax, Attributable to Parent Comprehensive income attributable to common stock Less: Comprehensive income attributable to noncontrolling interests Comprehensive Income, Net of Tax, Attributable to Noncontrolling Interest Comprehensive Income, Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income Equity (Textual) [Abstract] Equity (Textual) [Abstract] Equity. Minimum future licensing revenues remainder of current year Minimum future licensing revenues, remainder of current year. Remainder of 2011 Future amortization expense in the third full fiscal year 2014 The amount of amortization expense expected to be recognized during the third full fiscal year. Future amortization expense in the fifth full fiscal year and thereafter Thereafter Future amortization expense year in the fifth full fiscal year and thereafter. Actual Tax Benefit Expense from Vested Restricted Stock Actual tax benefit expense from vested restricted stock. Actual tax benefit (expense) from vested restricted stock Subordinated Borrowing, Interest Rate Interest rate of convertible subordinated notes Deferred Revenue, Total Fiber optic deferred revenue Actual tax benefit (expense) related to stock-based compensation expense Actual tax benefit (expense) related to stock-based compensation expense Actual tax benefit (expense) related to stock-based compensation expense Actual tax benefit, expense, related to stock-based compensation expense. Operating Leases, Future Minimum Payments Due Total minimum lease payments Commitments and Contingencies (Textual) [Abstract] Commitments and Contingencies (Textual) [Abstract] Commitments and contingencies. Operating Leases, Rent Expense Rent expense related to operating leases Employer's liability insurance claims deductible Employer's liability claims subject to deductible per occurrence Employer's liability claims deductible amount per occurrence. Worker's compensation insurance claims deductible Worker's compensation claims per occurrence Workers' compensation insurance claims deductible. Liability for Claims and Claims Adjustment Expense Liability for Claims and Claims Adjustment Expense, Total Gross amount accrued for insurance claims Line of Credit Facility, Fair Value of Amount Outstanding Letters of credit outstanding issued under credit facility Estimated cost to complete bonded projects Estimated cost to complete bonded projects. Estimated cost to complete bonded projects Segment Information (Textual) [Abstract] Segment Information (Textual) Segment information. Electric Power Segment [Member] Electric Power [Member] Electric power segment. Natural Gas and Pipeline Segment [Member] Natural Gas and Pipeline [Member] Natural gas and pipeline segment. Telecommunications Segment [Member] Telecommunications segment. Telecommunications [Member] Fiber Optic Licensing Segment [Member] Fiber Optic Licensing [Member] Fiber optic licensing segment. Corporate and Non Allocated Costs [Member] Corporate and non-allocated costs [Member] Corporate and non-allocated costs. Operating Leases of Lessee Disclosure [Text Block] Minimum Lease Payments Operating Leases, Future Minimum Payments Due [Abstract] Minimum Lease Payments Guarantor Obligations, Maximum Exposure, Undiscounted Maximum guaranteed residual value Schedule of Segment Reporting Information, by Segment [Text Block] Summarized financial information Segment Reporting Information, Operating Income (Loss) [Abstract] Summarized financial information Entity-Wide Disclosure on Geographic Areas, Revenue from External Customers Attributed to Foreign Countries Revenues from foreign operations General liability insurance claims deductible General liability insurance claims deductible amount per occurrence. General liability insurance claims deductible Auto liability insurance claims deductible Auto liability insurance claims deductible Auto liability insurance claims deductible amount per occurrence. Preferred Stock, Par or Stated Value Per Share Preferred stock, par value Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred stock, shares issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Preferred Stock, $.00001 par value, 1 share authorized, issued and outstanding Preferred Stock, Value, Issued Exchangeable Shares of Subsidiary [Member] Exchangeable Shares of Subsidiary [Member] Exchangeable shares of subsidiary. Business Acquisition, Cost of Acquired Entity, Liabilities Incurred Repayment of cash in acquiree debt Payment of cash to repay acquiree debt Allowance for Doubtful Accounts Receivable Total allowances for doubtful accounts Schedule of Business Acquisitions by Acquisition, Equity Interest Issued or Issuable [Table] Equity Interest Issued or Issuable by Type [Axis] Equity Interest Issued or Issuable, Type [Domain] Business Acquisition, Equity Interests Issued or Issuable [Line Items] Finite Lived Intangible Assets Foreign Currency Adjustments Foreign Currency Adjustments Finite lived intangible assets foreign currency adjustments. Trade Names [Member] Payment of Fire Suppression Costs Payment of fire suppression costs. Payment of fire suppression costs Other Damages Other damages. Other damages Series F Preferred Stock [Member] Series F Preferred Stock [Member] Series F Preferred Stock Class of Stock [Axis] Class of Stock [Domain] Entity Common Stock, Shares Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Vesting period for restricted stock and restricted stock units Entity-Wide Disclosure on Geographic Areas, Long-Lived Assets in Foreign Countries Property and equipment held in foreign countries Schedule of Long-term Debt Instruments [Table] Debt Instrument [Line Items] Schedule of Goodwill [Table] Goodwill [Line Items] Schedule of Segment Reporting Information, by Segment [Table] Segment Reporting Information [Line Items] Future Amortization Expense in Second Full Fiscal Year The amount of amortization expense expected to be recognized during the second full fiscal year. 2013 Future Amortization Expense in Fourth Full Fiscal Year The amount of amortization expense expected to be recognized during the fourth full fiscal year. 2015 Long Term Insurance Claims Long-term insurance claims Long-term insurance claims. Consolidation, Policy [Text Block] Principles of Consolidation Cash and Cash Equivalents, Policy [Text Block] Cash and Cash Equivalents Receivables, Policy [Text Block] Current and Long-term Accounts and Notes Receivable and Allowance for Doubtful Accounts Goodwill and Intangible Assets, Policy [Text Block] Goodwill and Other Intangibles Revenue Recognition, Policy [Text Block] Revenue Recognition Income Tax, Policy [Text Block] Income Taxes Interim Condensed Consolidated Financial Information [Policy Text Block] Interim Condensed Consolidated Financial Information Interim condensed consolidated financial information policy. Convertible Common Stock [Member] Exchangeable Shares Exchangeable Shares, no par value, 3,909,110 shares authorized, issued and outstanding Notes Payable, Current Notes payable Gains (Losses) on Extinguishment of Debt Loss on early extinguishment of debt Non Cash Portion of Loss on Early Extinguishment of Debt Non-cash loss on early extinguishment of debt Non-cash loss on early extinguishment of debt Amount represents the difference between the fair value of the payments made and the carrying amount of the debt at the time of its extinguishment, less the cash prepayment penalty. Repayments of Convertible Debt Payments on convertible notes Payments on convertible notes Redemption Premium on Convertible Subordinated Notes Redemption premium on convertible subordinated notes Redemption premium on convertible subordinated notes Redemption premium on convertible subordinated notes Redemption premium on convertible subordinated notes. Long Term Incentive Plans (Textual) [Abstract] Long term incentive plans. Long Term Incentive Plans (Textual) [Abstract] Earnings Per Share, Policy [Text Block] Earnings Per Share Information Payments for Repurchase of Common Stock Repurchase of common stock Repurchase of common stock Stockholders' Equity, Policy [Text Block] Comprehensive Income Incremental Common Shares Attributable to Contingently Issuable Shares Effect of shares in escrow Base Rate in Excess of Federal Funds Rate Base rate in excess of Federal Funds Rate Base rate in excess of Federal Funds Rate. Cross Default Provisions Cross default provisions with debt instruments exceeding this amount Cross-default provisions. Treasury Stock, Shares, Acquired Treasury stock acquired Treasury Stock, Value, Acquired, Cost Method Value of treasury stock acquired, cost method Common Stock Available for Awards Pursuant to Plan Common Stock available for awards pursuant to the 2011 plan Common stock available for awards pursuant to the plan. Operating Leases Future Minimum Payments Due, Remainder of the Current Year Remainder of 2011 For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due in the remainder of the current year relating to leases defined as operating. Operating Leases Future Minimum Payments, Due in the First Full Year 2012 For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the first full year of the balance sheet date relating to leases defined as operating. Operating Leases Future Minimum Payments, Due in the Second Full Year 2013 For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the second full year of the balance sheet date relating to leases defined as operating. Operating Leases Future Minimum Payments, Due in the Third Full Year 2014 For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the third full year of the balance sheet date relating to leases defined as operating. Noncontrolling Interest, Ownership Percentage by Parent Percentage of Interest In Unincorporated Joint Venture Concentration Risk, Percentage Percentage of billed and accrued receivables for significant customer Health Care Deductible Health care deductible. Employee health care benefit plans subject to deductible per claimant Operating Leases Future Minimum Payments Due in the Fourth Full Year For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fourth full year of the balance sheet date relating to leases defined as operating. 2015 New accounting pronouncements not yet adopted [Policy Text Block] Accounting Standards Not Yet Adopted New accounting pronouncements not yet adopted. Redemption price as a percentage of the principal amount of convertible subordinated notes Redemption price as a percentage of the principle amount of the 3.75% convertible subordinated notes Redemption price as a percentage of the principal amount of convertible subordinated notes. Minimum Future Licensing Revenues in First Full Year Minimum future licensing revenues, in first full year. 2012 Minimum Future Licensing Revenues in Third Full Year Minimum future licensing revenues, in third full year. 2014 Minimum Future Licensing Revenues in Second Full Year Minimum future licensing revenues, in second full year. 2013 Minimum Future Licensing Revenues in Fourth Full Year Minimum future licensing revenues, in fourth full year. 2015 Future Amortization Expense in First Full Fiscal Year 2012 The amount of amortization expense expected to be recognized during the first full fiscal year. Tax Benefit Related to Stock Based Compensation Expense Total tax benefit related to stock-based compensation expense Total tax benefit related to stock-based compensation expense Tax benefit related to stock-based compensation expense. Operating Leases Future Minimum Payments Due after Fourth Full Year for Interim Periods or after Five Full Years for Year End Reporting Periods Thereafter For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due after fourth full year for interim periods or after five full years for year end reporting periods on leases defined as operating. Number of Lawsuits Related to Wildfire Litigation Number of lawsuits related to California wildfire litigation Number of lawsuits related to California wildfire litigation. Additional Business and Organization (Textual) [Abstract] Additional Business and Organization (Textual) [Abstract] Additional business and organization. Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Additional Long Term Incentive Plans (Textual) [Abstract] Additional Long Term Incentive Plans (Textual) [Abstract] Additional long term incentive plans. Payments to Acquire Equity Method Investments Payment to acquire equity method investment Equity method investment made during the period Initial capital contribution for acquisition of HEP Payment to acquire equity method investments Equity Method Investment, Ownership Percentage Acquired ownership interest in HEP Common Stock Withheld for Settlement of Employee Tax Liabilities [Member] Common stock withheld for settlement of employee tax liabilities. Common stock withheld for settlement of employee tax liabilities Common Stock Repurchased Under Repurchase Plan [Member] Common stock repurchased under repurchase plan. Common stock repurchased under repurchase plan Schedule of Stock by Class [Table] Class of Stock [Line Items] Equity Additional (Textual) [Abstract] Equity (Additional Textual) [Abstract] Equity. Outstanding Performance Bonds Total amount of outstanding performance bonds The total amount of outstanding performance bonds. Number of Insurers Participating under a Reservation of Rights Number of Insurers Participating Under a Reservation of Rights Number of insurers participating under a reservation of rights. Schedule of Finite-Lived Intangible Assets by Major Class [Table] Finite-Lived Intangible Assets [Line Items] Fiber Optic Licensing Terms Minimum in Years Fiber Optic Licensing terms, minimum in years Fiber optic licensing terms minimum in years. Fiber Optic Licensing Terms Maximum in Years Fiber Optic Licensing terms, maximum in years Fiber optic licensing terms, maximum in years. Number of Shares of Common Stock Received for Each Exchangeable Share Number of shares of common stock received for each exchangeable share. Number of shares of Common stock received for each exchangeable share Damages Caused to Acreage Due to Wildfire Amount of acreage damaged due to wildfire Damages caused to acreage due to wildfire. Damages Caused to Homes and Structures Due to Wildfire Number of homes and structures damaged due to wildfire Damages caused to homes and structures due to wildfire. Alleged Deaths Caused by Wildfire Alleged deaths caused by wildfire. Alleged deaths caused by wildfire Alleged Number of Personal Injuries Caused by Wildfire Alleged number of personal injuries caused by wildfire. Alleged number of personal injuries caused by wildfire Land Damaged Due to Wildfire in Acres Land damaged due to wildfire, in acres Land damaged due to wildfire, in acres. Number of Insurers Claiming Coverage Does not Exist Number of Insurers Claiming Coverage does not exist Number of insurers claiming coverage does not exist. Subsequent Event [Line Items] Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Distributions to noncontrolling interest Decrease in Fair Value of Reporting Units Considered for Impairment Calculation Decrease in fair value of reporting units considered, for impairment calculation Decrease in fair value of Reporting units considered, for impairment calculation. Agreed Amount of Loan to Indirect Parent of LLC Agreed amount of loan to indirect parent of LLC Agreed amount of loan to indirect parent of LLC. Valard Construction LP [Member] Valard construction LP. Valard Construction LP [Member] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Addition to Indefinite Lived Intangible Assets Addition to indefinite lived intangible assets Addition to indefinite lived intangible assets. Investments in Affiliates and Other Entities [Policy Text Block] Investments in Affiliates and Other Entities Investments in affiliates and other entities policy. Schedule of New Accounting Pronouncement and Changes in Accounting Principles [Policy Text Block] Adoption of New Accounting Pronouncements Schedule of new accounting pronouncements and changes in accounting principles. Common Stock Repurchased Related to Repurchase Plan [Policy Text Block] Repurchase of Common Stock Common stock repurchased related to repurchase plan. Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options Actual tax benefit (expense) from options exercised Commitments and Contingencies Commitments and Contingencies Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Number of shares issued for acquisition of a company Number of share issued, common stock, acquisition Long-term Debt, Gross Debt Instrument, Face Amount Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Unrecognized compensation cost, related to unvested restricted stock, total Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Expected weighted average period to recognize compensation cost on restricted stock (in years) Operating Income (Loss) Operating income (loss) Operating income Operating income Sales Revenue, Services, Net Revenues from external customers Sales Revenue, Services, Net, Total Revenues Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound Estimated amount believed to be reasonably possible for unrecognized tax benefits to decrease over the next 12 months related to uncertain tax positions due to the expiration of certain statutes of limitations Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net, Total Carrying value of the investments held by Quanta in variable interest entities Statement, Business Segments [Axis] Segment [Domain] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Goodwill, Impaired, Accumulated Impairment Loss Accumulated impairment Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Segment Reporting, Policy [Policy Text Block] Subsequent Event [Abstract] Goodwill, Gross Goodwill Goodwill, Purchase Accounting Adjustments Purchase price adjustments related to prior periods Restricted Stock Units (RSUs) [Member] Stock Repurchase Program, Authorized Amount Aggregate authorized amount of common stock to be repurchased Goodwill, Other Changes Operating unit reorganization Insurance Settlements Receivable Related insurance recoveries receivables Insurance Settlements Receivable, Noncurrent Related insurance recoveries receivables included in other assets net Insurance Settlements Receivable, Current Related insurance recoveries/receivables included in prepaid expenses and other current assets Subsequent Events [Text Block] Subsequent Event Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value Measurements Schedule of Comprehensive Income (Loss) [Table Text Block] Comprehensive Income Business and Organization [Abstract] Debt Obligations [Abstract] Segment Information [Abstract] Minimum Future Licensing Revenues [Table Text Block] Minimum future licensing revenues Minimum future licensing revenues. Goodwill and Other Intangible Assets [Abstract] Commitments and Contingencies [Abstract] Estimated future aggregate amortization expense of intangible assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Basic and diluted earnings per share Goodwill, Translation Adjustments Non-cash compensation expense and related tax benefits Segment Reporting Use of Estimates, Policy [Policy Text Block] Use of Estimates and Assumptions Summary of Significant Accounting Policies [Abstract] NET INCOME: Net Income (Loss) Available to Common Stockholders, Diluted [Abstract] NET INCOME: Finite Lived Intangible Assets Future Amortization Expense for Next Five Years and Thereafter Total intangible assets subject to amortization The aggregate estimated amortization expense for each of the five succeeding fiscal years and thereafter related to finite-lived intangible assets subject to amortization. Foreign Currency Transactions and Translations [Policy Text Block] Functional Currency and Translation of Financial Statements Minimum Number of Shares That can be Exchanged by Exchangeable Shareholders Unless Number of Remaining Exchangeable Shares Registered in Name of Holder is Less Minimum number of shares that can be exchanged by exchangeable shareholders unless number of remaining exchangeable shares registered in name of holder is less. Minimum number of shares that can be exchanged by exchangeable shareholders unless the number of remaining exchangeable shares registered in the name of the holder is less Finite-Lived Intangible Assets, Net Finite-Lived Intangible Assets, Net, Total Intangible Assets, Net, subject to amortization Indefinite-lived Intangible Assets Indefinite-lived Intangible Assets, Ending Balance Indefinite-lived Intangible Assets, Beginning Balance Intangible Assets, Net, not subject to amortization Long-term Incentive Plans [Abstract] New Accounting Pronouncements [Text Block] New accounting pronouncements. NEW ACCOUNTING PRONOUNCEMENTS Compensation Related Costs, Policy [Policy Text Block] Share Based Compensation Common Stock, No Par Value Exchangeable shares, par value Allocated Share Based Compensation Expense Compensation expense related to Restricted Stock Units Limited Vote Common Stock [Member] Limited Vote Common Stock [Member] Limited Vote Common Stock, $.00001 par value, 0 and 3,345,333 shares authorized, and 0 and 432,485 shares issued and outstanding, respectively Limited vote common stock. Fraction of Vote Common Stockholders were Allowed on all Matters Other Than Election of Board Fraction of vote Common Stockholders were allowed on all matters other than election of the Board Fraction of vote Common Stockholders were allowed on all matters other than election of the Board. Number of Common Stock Shares Received for Each Share of Common Stock Converted Number of common stock shares received for each share of Common Stock converted Number of common stock shares received for each share of common stock converted. Liabilities under Compensation Plan Liabilities under Compensation Plan Liabilities under compensation plan. Number of Preferred Stock Issued to Voting Trust Number of preferred Stock issued to voting trust Number of preferred Stock issued to voting trust. Payments to Acquire Businesses, Net of Cash Acquired Cash paid for acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired, Total Cash paid for acquisitions, net of cash acquired Mergers, Acquisitions and Dispositions Disclosures [Text Block] ACQUISITIONS Acquisitions [Abstract] Coe Group [Member] Coe Group [Member] Coe group. Business Acquisition, Purchase Price Allocation, Current Assets Current assets Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment Property and equipment Business Acquisition, Purchase Price Allocation, Other Noncurrent Assets Other assets Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets Identifiable intangible assets Business Acquisition, Purchase Price Allocation, Current Liabilities Current liabilities Business Acquisition, Purchase Price Allocation, Goodwill Amount Goodwill Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net [Abstract] Business acquisition purchase price allocation assets acquired and liabilities assumed Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Line Items] Business Acquisition, Pro Forma Information [Table Text Block] Unaudited supplemental pro forma results of operations Business Acquisition, Pro Forma Information [Abstract] Unaudited supplemental pro forma results of operations Acquisitions (Textual) [Abstract] Acquisitions. Acquisitions Business Acquisition, Pro Forma Revenue Revenues Percentage of Capital Stock of Direct Foreign Subsidiaries Required to Secure Credit Agreement Percentage of capital stock of direct foreign subsidiaries required to secure credit agreement. Percentage of capital stock of direct foreign subsidiaries required to secure credit agreement Number Of Customers Representing Ten Percent Or More Of Consolidated Revenues Number of customers representing ten percent or more of consolidated revenues Number of customers representing ten percent or more of consolidated revenues. Percent of Consolidated Revenues for One Major Customer Percent of consolidated revenues for one major customer. Percent of consolidated revenues for one major customer Percent of Consolidated Revenues for Second Major Customer Percent of consolidated revenues for second major customer. Percent of consolidated revenues for second major customer Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Business acquisition purchase price allocation assets acquired and liabilities assumed Business Acquisition, Cost of Acquired Entity, Purchase Price Fair value of total consideration transferred Business Acquisition, Purchase Price Allocation, Deferred Income Taxes, Asset (Liability), Net Deferred tax liabilities, net Business Acquisition, Purchase Price Allocation, Other Noncurrent Liabilities Other long-term liabilities Business Acquisition, Purchase Price Allocation, Assets Acquired (Liabilities Assumed), Net Total identifiable net assets Business Acquisition Pro Forma Earnings Per Share [Abstract] Earnings per share attributable to common stock: Business acquisition pro forma earnings per share. Business Acquisition, Pro Forma Earnings Per Share, Basic Basic Business Acquisition, Pro Forma Earnings Per Share, Diluted Diluted Business Acquisitions Pro Forma Selling General and Administrative Expenses Selling, general and administrative expenses Business acquisitions pro forma selling, general and administrative expenses. Business Acquisitions Pro Forma Amortization of Intangible Assets Amortization of intangible assets Business acquisitions pro forma amortization of intangible assets. Business Acquisition, Purchase Price Allocation, Current Assets, Receivables Accounts receivables with fair value Swing Line Loans [Member] Swing line loans. Swing Line Loans [Member] Debt Obligations (Additional Textual) [Abstract] Debt obligations. Debt Obligations (Additional Textual) [Abstract] Maximum [Member] Maximum [Member] Minimum [Member] Minimum [Member] Performance Letter of Credit [Member] Performance Letter of Credit [Member] Performance letter of credit. Rate in Excess of Eurocurrency Rate One possible rate is this rate in excess of the Eurocurrency Rate Rate in excess of Eurocurrency rate. Line of Credit Facility [Table] Line of Credit Facility [Axis] Line of Credit Facility, Lender [Domain] Range [Axis] Range [Domain] Line of Credit Facility [Line Items] Consideration [Abstract] Consideration. Consideration: Summary of Significant Accounting Policies (Textual) [Abstract] Summary of Significant Accounting Policies (Textual) [Abstract] Summary of significant accounting policies. Additional Subsequent Events (Textual) [Abstract] Subsequent Event (Textual) [Abstract] Additional subsequent events. Business Acquisitions Pro Forma Gross Profit Gross profit Business acquisitions pro forma gross profit. Number of Customers Representing Accounts Receivable Threshold Percentage Number of customers representing ten percent or more of accounts receivables Number of customer represent ten percent or more of accounts receivable. Minimum Percentage of Revenue Minimum percentage of revenue Minimum percentage of revenue. Utilimap Corporation [Member] Utilimap corporation. Utilimap Corporation [Member] Additional Per Share Information (Textual) [Abstract] Additional Per Share Information (Textual) [Abstract] Additional per share information. Interest Rate in Excess of Eurodollar Rate Interest rate in excess of Eurodollar Rate Interest rate in excess of Eurodollar rate. Interest Rate in Excess of Base Rate Interest rate in excess of Base Rate Interest rate in excess of base rate. Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Commitment fee Long Term Purchase Commitment Amount Remainder of Current Year Committed capital expenditures for current year Long term purchase commitment amount remainder of current year. Long Term Purchase Commitment Amount Thereafter Committed capital expenditures, thereafter Long term purchase commitment amount thereafter. Revenues Contributed by Acquisitions Revenues contributed by acquisitions. Revenues contributed by acquisitions Two Other Third Quarter Two Thousand Eleven Acquisitions [Member] Two other third quarter 2011 acquisitions. Two Other third quarter 2011 acquisitions [Member] Income Before Income Taxes Contributed by Acquisitions Income before income taxes contributed by acquisitions Income before income taxes contributed by acquisitions. Business Acquisitions Pro Forma Net Income Loss Attributable to Common Stock Net income attributable to common stock Business acquisitions pro forma net income loss attributable to common stock. Minimum Percentage of Billed and Unbilled Accounts Receivable Minimum percentage of billed and unbilled accounts receivable. Minimum percentage of billed and unbilled accounts receivable Letter of Credit Fee Letter of credit fee. Letter of credit fee Cash Paid for Non Compete Cash paid for non-compete agreement Cash paid for non-compete. Debt issuance and amendment costs Payments of Debt Issuance Costs Common Stock and Exchangeable Shares [Member] Common stock and exchangeable shares. Common Stock and Exchangeable Shares [Member] Addition to Finite Lived Intangible Assets Additions Addition to finite lived intangible assets. Revolving Loans and Letter of Credit in Alternative Currencies [Member] Revolving loans and letter of credit in alternative currencies. Revolving Loans and Letter of Credit in Alternative Currencies [Member] Number of Common Stock reclassified and converted for common stock Number of limited vote common stock reclassified and converted for common stock. Number of Limited Vote Common Stock reclassified and converted for common stock Number of Common Stock Shares Issued on Reclassification and Conversion of Common Stock Number of common stock shares issued on reclassification and conversion of limited vote common stock Number of common stock shares issued on reclassification and conversion of limited vote common stock. Number of Common Stock Exchanged for Common Stock Number of limited vote common stock exchanged for common stock. Number of Limited Vote Common Stock exchanged for common stock Number of Common Stock Shares Issued on Exchange of Common Stock Number of common stock shares issued on exchange of limited vote common stock Number of common stock shares issued on exchange of limited vote common stock. Common Stock [Member] Intangible Assets Gross, Excluding Goodwill Intangible assets gross, excluding goodwill. Intangible assets, gross Goodwill, Acquired During Period Goodwill acquired during the period Number of Businesses Acquired Number of business acquisitions completed Loss Contingency, Related Receivable Carrying Value Insurance recovery receivable McGregor, Coe and Two Other Acquisitions [Member] McGregor, Coe and Two Other Acquisitions [Member] McGregor coe and two other acquisitions. McGregor Construction Group [Member] McGregor construction group. McGregor Construction Group [Member] Interest Rate in Excess of Eurocurrency Rate Domestic Plus Mandatory Cost Interest rate in excess of Eurocurrency rate applicable to domestic borrowings only, plus Mandatory Cost Interest rate in excess of Eurocurrency rate domestic. Interest Rate in Excess of Base Rate Domestic Interest rate in excess of Base Rate, domestic borrowings only Interest rate in excess of base rate domestic. Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Loss Contingency, Loss in Period Liability recorded for fire claims Payments to Acquire Investments Cash paid for other investments Amount loaned to indirect parent of LLC Interest rate of Credit Agreement for foreign borrowings plus Mandatory Costs Interest rate of Credit Agreement for foreign borrowings, plus Mandatory Costs. Interest rate of Credit Agreement for foreign borrowings, plus Mandatory Costs Prior Credit Facility [Member] Prior Credit Facility. Prior Credit Facility [Member] Addition To Intangible Assets Additions to intangible assets. Additions to intangible assets Loss Contingencies [Table] Loss Contingency, Nature [Domain] Loss Contingencies by Nature of Contingency [Axis] California Wildfire San Diego [Member] California wildfire, San Diego. California Wildfire Amador County [Member] California wildfire, Amador County. Loss Contingencies [Line Items] Commitments and Contingencies (Textual) [Abstract] Loss Contingency Accrual, Disclosures [Abstract] Commitments and Contingencies (Textual) [Abstract] Cash paid Business acquisition cost of acquired entity, cash paid and liabilities incurred. Business Acquisition Cost Of Acquired Entity Cash Paid And Liabilities Incurred