Document and Entity Information
| Document and Entity Information | Sep. 03, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | OLYMPIC STEEL INC |
| Security Exchange Name | NASDAQ |
| Amendment Flag | false |
| Entity Central Index Key | 0000917470 |
| Document Type | 8-K |
| Document Period End Date | Sep. 3, 2021 |
| Entity Incorporation State Country Code | OH |
| Entity File Number | 0-23320 |
| Entity Tax Identification Number | 34-1245650 |
| Entity Address, Address Line One | 22901 Millcreek Boulevard |
| Entity Address, Address Line Two | Suite 650 |
| Entity Address, City or Town | Highland Hills |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 44112 |
| City Area Code | (216) |
| Local Phone Number | 292-3800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, without par value |
| Trading Symbol | ZEUS |
| Entity Emerging Growth Company | false |