| Document and Entity Information | Feb. 26, 2020 |
| Document and Entity Information [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 14, 2021 |
| Entity File Number | 000-22012 |
| Entity Registrant Name | Winmark Corporation |
| Entity Incorporation, State or Country Code | MN |
| Entity Tax Identification Number | 41-1622691 |
| Entity Address, Address Line One | 605 Highway 169 North |
| Entity Address, Adress Line Two | Suite 400 |
| Entity Address, City or Town | Minneapolis |
| Entity Address, State or Province | MN |
| Entity Address, Postal Zip Code | 55441 |
| City Area Code | 763 |
| Local Phone Number | 520-8500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, no par value per share |
| Trading Symbol | WINA |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000908315 |
| Amendment Flag | false |
