| Cover Page | May 04, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 4, 2021 |
| Entity Registrant Name | HERITAGE-CRYSTAL CLEAN, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-33987 |
| Entity Tax Identification Number | 26-0351454 |
| Entity Address, Address Line One | 2175 Point Boulevard |
| Entity Address, Address Line Two | Suite 375 |
| Entity Address, City or Town | Elgin |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60123 |
| City Area Code | 847 |
| Local Phone Number | 836-5670 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | HCCI |
| Security Exchange Name | NASDAQ |
| Entity Central Index Key | 0001403431 |
| Amendment Flag | false |
