| Cover Page Document | Feb. 01, 2021 | Aug. 21, 2020 |
| Cover Page [Abstract] | ||
| Amendment Flag | false | |
| Entity Emerging Growth Company | false | |
| Title of 12(b) Security | Common Stock, $0.001 par value | |
| Written Communications | false | |
| Entity Address, Address Line One | 118 Second Avenue SE | |
| Entity Incorporation, State or Country Code | IA | |
| Document Type | 8-K | |
| Document Period End Date | Feb. 1, 2021 | |
| Entity Registrant Name | United Fire Group Inc | |
| Entity File Number | 001-34257 | |
| Entity Tax Identification Number | 45-2302834 | |
| Entity Address, City or Town | Cedar Rapids | |
| Entity Address, State or Province | IA | |
| Entity Address, Postal Zip Code | 52401 | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Trading Symbol | UFCS | |
| Security Exchange Name | NASDAQ | |
| City Area Code | 319 | |
| Local Phone Number | 399-5700 | |
| Entity Central Index Key | 0000101199 |
