Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Additional Information (Detail)

v2.4.1.9
Commitments and Contingencies - Additional Information (Detail) (USD $)
0 Months Ended 3 Months Ended 1 Months Ended 12 Months Ended
Oct. 09, 2013
Mar. 31, 2015
Customer
Mar. 31, 2014
Customer
Dec. 31, 2014
Dec. 31, 2014
Jul. 31, 2014
Dec. 31, 2011
Apr. 21, 2010
mi
Commitment And Contingencies [Line Items]                
Outstanding capital commitment   $ 9,300,000pwr_OutstandingCapitalCommitments            
Rent expense related to operating leases   49,500,000us-gaap_LeaseAndRentalExpense 34,800,000us-gaap_LeaseAndRentalExpense          
Maximum guaranteed residual value   459,500,000us-gaap_GuaranteeObligationsMaximumExposure            
Number of customers representing ten percent or more of consolidated revenues   0pwr_NumberOfCustomersRepresentingTenPercentOrMoreOfConsolidatedRevenues 0pwr_NumberOfCustomersRepresentingTenPercentOrMoreOfConsolidatedRevenues          
Number of customers representing ten percent or more of net position   0pwr_NumberOfCustomersRepresentingNetPositionThreshold   0pwr_NumberOfCustomersRepresentingNetPositionThreshold 0pwr_NumberOfCustomersRepresentingNetPositionThreshold      
Gross amount accrued for insurance claims   173,400,000us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense   170,200,000us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense 170,200,000us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense      
Long-term insurance claims   139,400,000pwr_LongTermInsuranceClaims   130,800,000pwr_LongTermInsuranceClaims 130,800,000pwr_LongTermInsuranceClaims      
Related insurance recoveries/receivables   8,900,000us-gaap_InsuranceSettlementsReceivable   9,100,000us-gaap_InsuranceSettlementsReceivable 9,100,000us-gaap_InsuranceSettlementsReceivable      
Related insurance recoveries/receivables included in prepaid expenses and other current assets   900,000us-gaap_InsuranceSettlementsReceivableCurrent   800,000us-gaap_InsuranceSettlementsReceivableCurrent 800,000us-gaap_InsuranceSettlementsReceivableCurrent      
Related insurance recoveries/receivables included in other assets net   8,000,000us-gaap_InsuranceSettlementsReceivableNoncurrent   8,300,000us-gaap_InsuranceSettlementsReceivableNoncurrent 8,300,000us-gaap_InsuranceSettlementsReceivableNoncurrent      
Letters of credit and bank guarantees under the credit facility   328,500,000us-gaap_LettersOfCreditOutstandingAmount            
Total amount of outstanding performance bonds   2,700,000,000pwr_OutstandingPerformanceBondsAmount            
Estimated cost to complete bonded projects   504,000,000pwr_EstimatedCostToCompleteBondedProjects            
Multi-employer plan withdrawal obligation           39,600,000us-gaap_MultiemployerPlansWithdrawalObligation 32,600,000us-gaap_MultiemployerPlansWithdrawalObligation  
Multi-employer plan withdrawal obligation, amount suggested by Plan which is different than amount recorded by company 6,900,000pwr_MultiemployerPlanWithdrawalObligationAmountSuggestedByPlanDifferentThanAmountRecordedByCompany              
Multi-employer plan withdrawal obligation complete withdrawal 4,800,000pwr_MultiemployerPlanWithdrawalObligationCompleteWithdrawal              
Multi-employer plan withdrawal obligation accrued   2,800,000pwr_MultiemployerPlanWithdrawalObligationAccrued            
Cash proceeds deposited in Escrow account 2,100,000pwr_EscrowedFundsToCoverMultipleEmployerPlansLiabilityOfAcquiredCompany              
Pre-acquisition non-U.S.tax obligations and indemnification asset amount recorded   11,000,000us-gaap_BusinessCombinationIndemnificationAssetsAmountAsOfAcquisitionDate            
Pre-acquisition non-U.S.tax obligations and indemnification liability amount recorded   11,000,000us-gaap_AccruedPayrollTaxesCurrentAndNoncurrent            
Alberta Power Line [Member]                
Commitment And Contingencies [Line Items]                
Length of electrical transmission line to be constructed under contract   500pwr_LengthOfTransmissionLine
/ us-gaap_TypeOfArrangementAxis
= pwr_AlbertaPowerLineMember
           
Sunrise Powerlink Project [Member]                
Commitment And Contingencies [Line Items]                
Length of electrical transmission line to be constructed under contract               117pwr_LengthOfTransmissionLine
/ us-gaap_TypeOfArrangementAxis
= pwr_SunrisePowerlinkProjectMember
Proceeds from customers       65,000,000us-gaap_ProceedsFromCustomers
/ us-gaap_TypeOfArrangementAxis
= pwr_SunrisePowerlinkProjectMember
       
Fiber Optic Committed Capital [Member]                
Commitment And Contingencies [Line Items]                
Estimated committed capital remainder of current year   26,100,000us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
/ us-gaap_StatementScenarioAxis
= pwr_FiberOpticCommittedCapitalMember
           
Estimated committed capital expenditures in 2016   200,000us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary
/ us-gaap_StatementScenarioAxis
= pwr_FiberOpticCommittedCapitalMember
           
Vehicle Fleet Committed Capital [Member]                
Commitment And Contingencies [Line Items]                
Estimated committed capital remainder of current year   5,600,000us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
/ us-gaap_StatementScenarioAxis
= pwr_VehicleFleetCommittedCapitalMember
           
Minimum [Member]                
Commitment And Contingencies [Line Items]                
Multi-employer plan withdrawal obligation   40,100,000us-gaap_MultiemployerPlansWithdrawalObligation
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
           
Minimum [Member] | Sales Revenue, Net [Member] | Customer Concentration Risk [Member]                
Commitment And Contingencies [Line Items]                
Concentration risk percentage   10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= us-gaap_SalesRevenueNetMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
         
Minimum [Member] | Net Position [Member] | Customer Concentration Risk [Member]                
Commitment And Contingencies [Line Items]                
Concentration risk percentage   10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= pwr_NetPositionMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
    10.00%us-gaap_ConcentrationRiskPercentage1
/ us-gaap_ConcentrationRiskByBenchmarkAxis
= pwr_NetPositionMember
/ us-gaap_ConcentrationRiskByTypeAxis
= us-gaap_CustomerConcentrationRiskMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
     
Maximum [Member]                
Commitment And Contingencies [Line Items]                
Multi-employer plan withdrawal obligation   55,400,000us-gaap_MultiemployerPlansWithdrawalObligation
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
           
Lorenzo Benton v Telecom Network Specialists Inc [Member]                
Commitment And Contingencies [Line Items]                
Number of staffing Agency   29pwr_NumberOfAgencies
/ dei_LegalEntityAxis
= pwr_LorenzoBentonvTelecomNetworkSpecialistsIncMember
           
Lorenzo Benton v Telecom Network Specialists Inc [Member] | Class Damage [Member]                
Commitment And Contingencies [Line Items]                
Amount sought by plaintiff   16,000,000pwr_LossContingencyDamagesSoughtValueByPlaintiff
/ dei_LegalEntityAxis
= pwr_LorenzoBentonvTelecomNetworkSpecialistsIncMember
/ us-gaap_OtherCommitmentsAxis
= pwr_ClassDamageMember
           
Lorenzo Benton v Telecom Network Specialists Inc [Member] | Attorney Fees [Member]                
Commitment And Contingencies [Line Items]                
Amount sought by plaintiff   $ 5,000,000pwr_LossContingencyDamagesSoughtValueByPlaintiff
/ dei_LegalEntityAxis
= pwr_LorenzoBentonvTelecomNetworkSpecialistsIncMember
/ us-gaap_OtherCommitmentsAxis
= pwr_AttorneyFeesMember