| Cover Page | Feb. 08, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Feb. 8, 2021 |
| Entity Registrant Name | Kforce Inc |
| Entity Incorporation, State or Country Code | FL |
| Entity File Number | 000-26058 |
| Entity Tax Identification Number | 59-3264661 |
| Entity Address, Address Line One | 1001 East Palm Avenue |
| Entity Address, City or Town | Tampa |
| Entity Address, State or Province | FL |
| Entity Address, Postal Zip Code | 33605 |
| City Area Code | 813 |
| Local Phone Number | 552-5000 |
| Title of 12(b) Security | Common Stock, $0.01 per share |
| Trading Symbol | KFRC |
| Security Exchange Name | NASDAQ |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0000930420 |
