Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.8.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2017
Nov. 02, 2017
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2017  
Document Fiscal Year Focus 2017  
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  
Common Stock Class Undefined    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   154,720,790
Series G Preferred Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   1
Exchangeable Shares Associated with Series G Preferred Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   449,929
Exchangeable Shares Not Associated with Preferred Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   36,183