Quarterly report pursuant to Section 13 or 15(d)

Document and Entity Information

v3.10.0.1
Document and Entity Information - shares
9 Months Ended
Sep. 30, 2018
Nov. 01, 2018
Document Information [Line Items]    
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Sep. 30, 2018  
Document Fiscal Year Focus 2018  
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 Emerging Growth Company false  
Entity Small Business false  
Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   146,030,722
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