Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

Document and Entity Information
9 Months Ended
Sep. 30, 2013
Oct. 31, 2013
Common Stock [Member]
Oct. 31, 2013
Exchangeable Shares [Member]
Document Information [Line Items]      
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Sep. 30, 2013    
Document Fiscal Year Focus 2013    
Document Fiscal Period Focus Q3    
Trading Symbol PWR    
Entity Registrant Name QUANTA SERVICES INC    
Entity Central Index Key 0001050915    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   212,360,276 3,500,000