Quarterly report pursuant to Section 13 or 15(d)

Segment Information - Additional Information (Detail)

v2.4.1.9
Segment Information - Additional Information (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Segment Reporting Information [Line Items]      
Number of reportable segments 3us-gaap_NumberOfReportableSegments    
Property and equipment $ 1,480,097us-gaap_PropertyPlantAndEquipmentNet   $ 1,480,128us-gaap_PropertyPlantAndEquipmentNet
Canada [Member]      
Segment Reporting Information [Line Items]      
Percentage of foreign revenues 88.00%pwr_PercentageOfForeignRevenue
/ us-gaap_StatementGeographicalAxis
= country_CA
84.00%pwr_PercentageOfForeignRevenue
/ us-gaap_StatementGeographicalAxis
= country_CA
 
Foreign Operations [Member]      
Segment Reporting Information [Line Items]      
Revenues 533,500us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= pwr_ForeignOperationsMember
456,200us-gaap_Revenues
/ us-gaap_StatementBusinessSegmentsAxis
= pwr_ForeignOperationsMember
 
Property and equipment $ 358,700us-gaap_PropertyPlantAndEquipmentNet
/ us-gaap_StatementBusinessSegmentsAxis
= pwr_ForeignOperationsMember
  $ 372,900us-gaap_PropertyPlantAndEquipmentNet
/ us-gaap_StatementBusinessSegmentsAxis
= pwr_ForeignOperationsMember