Document and Entity Information - shares |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
May 02, 2018 |
|
| Document Information [Line Items] | ||
| Document Type | 10-Q | |
| Amendment Flag | false | |
| Document Period End Date | Mar. 31, 2018 | |
| Document Fiscal Year Focus | 2018 | |
| Document Fiscal Period Focus | Q1 | |
| 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 | 149,609,186 | |
| 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 |