Quarterly report pursuant to Section 13 or 15(d)

Debt Obligations - Long-term Debt Obligations (Parenthetical) (Detail)

v2.4.1.9
Debt Obligations - Long-term Debt Obligations (Parenthetical) (Detail)
Mar. 31, 2015
Dec. 31, 2014
Minimum [Member] | Other Long Term Debt [Member]    
Debt Instrument [Line Items]    
Capital leases and Other long-term debt interest rates 1.40%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= pwr_OtherLongTermDebtMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
1.40%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= pwr_OtherLongTermDebtMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Minimum [Member] | Capital Leases [Member]    
Debt Instrument [Line Items]    
Capital leases and Other long-term debt interest rates 6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CapitalLeaseObligationsMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
6.00%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CapitalLeaseObligationsMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Maximum [Member] | Other Long Term Debt [Member]    
Debt Instrument [Line Items]    
Capital leases and Other long-term debt interest rates 4.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= pwr_OtherLongTermDebtMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
4.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= pwr_OtherLongTermDebtMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Maximum [Member] | Capital Leases [Member]    
Debt Instrument [Line Items]    
Capital leases and Other long-term debt interest rates 7.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CapitalLeaseObligationsMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
7.30%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_CapitalLeaseObligationsMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember