| Document and Entity Information Document | May 26, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 26, 2021 |
| Entity Registrant Name | COPART INC |
| Entity Central Index Key | 0000900075 |
| Current Fiscal Year End Date | --07-31 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-23255 |
| Entity Tax Identification Number | 94-2867490 |
| Entity Address, Address Line One | 14185 Dallas Parkway |
| Entity Address, Address Line Two | Suite 300 |
| Entity Address, City or Town | Dallas |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 75254 |
| City Area Code | 972 |
| Local Phone Number | 391-5000 |
| 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 $0.0001 |
| Trading Symbol | CPRT |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
