| Cover Page Document | Nov. 04, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 5, 2021 |
| Entity Registrant Name | United Fire Group Inc |
| Entity Incorporation, State or Country Code | IA |
| Entity File Number | 001-34257 |
| Entity Tax Identification Number | 45-2302834 |
| Entity Address, Address Line One | 118 Second Avenue SE |
| Entity Address, City or Town | Cedar Rapids |
| Entity Address, State or Province | IA |
| Entity Address, Postal Zip Code | 52401 |
| City Area Code | 319 |
| Local Phone Number | 399-5700 |
| 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, $0.001 par value |
| Trading Symbol | UFCS |
| Security Exchange Name | NASDAQ |
| Amendment Flag | false |
| Entity Central Index Key | 0000101199 |
