| Document and Entity Information | Apr. 30, 2021 |
| Cover Abstract | |
| Document Type | 8-K |
| Document Period End Date | Apr. 30, 2021 |
| Entity Registrant Name | UNITED STATES LIME & MINERALS, INC. |
| Entity Incorporation, State or Country Code | TX |
| Entity File Number | 0-4197 |
| Entity Tax Identification Number | 75-0789226 |
| Entity Address, Address Line One | 5429 LBJ FREEWAY, SUITE 230 |
| Entity Address, City or Town | DALLAS |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 75240 |
| City Area Code | 972 |
| Local Phone Number | 991-8400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, $0.10 par value |
| Trading Symbol | USLM |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000082020 |
| Amendment Flag | false |
| Current Fiscal Year End Date | --12-31 |
