Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

Document and Entity Information
9 Months Ended
Sep. 30, 2011
Oct. 28, 2011
Entity Registrant Name QUANTA SERVICES INC  
Entity Central Index Key 0001050915  
Document Type 10-Q  
Document Period End Date Sep. 30, 2011  
Amendment Flag false  
Document Fiscal Year Focus 2011  
Document Fiscal Period Focus Q3  
Current Fiscal Year End Date --12-31  
Entity Well-known Seasoned Issuer Yes  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   206,224,437
Convertible Common Stock [Member]
Entity Common Stock, Shares Outstanding   3,909,110