| Document and Entity Information | Aug. 03, 2021 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Aug. 3, 2021 |
| Entity File Number | 001-36870 |
| Entity Registrant Name | TopBuild Corp |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 47-3096382 |
| Entity Address, Address Line One | 475 North Williamson Boulevard |
| Entity Address, State or Province | FL |
| Entity Address, City or Town | Daytona Beach |
| Entity Address, Postal Zip Code | 32114 |
| City Area Code | 386 |
| Local Phone Number | 304-2200 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, par value $0.01 per share |
| Trading Symbol | BLD |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001633931 |
| Amendment Flag | false |
