| Pay vs Performance Disclosure - USD ($) | 12 Months Ended | |
| Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 |
| Pay vs Performance Disclosure [Table] | | | | |
| Pay vs Performance [Table Text Block] | 2022 Pay Versus Performance Table Fiscal Year SCT Compensation Actually Paid to PEO Average SCT Average Compensation Actually paid to non-PEO NEOs Value of Initial fixed $100 Investment Based on Net Income Revenue TSR Peer Group 2022 $ 5,564,913 $ 2,066,802 $ 1,982,332 $ 754,954 $ 146 $ 121 $ 75 $ 1,711 2021 $ 6,329,950 $ 11,686,235 $ 3,629,803 $ 6,925,993 $ 197 $ 150 $ 75 $ 1,580 2020 $ 6,653,318 $ 6,922,445 $ 2,844,349 $ 3,010,896 $ 108 $ 99 $ 56 $ 1,398 | | | |
| Company Selected Measure Name | •Revenue (and implied revenue growth) | | | |
| Named Executive Officers, Footnote [Text Block] | Mr. Dunkel, current Chairman and non-executive employee of Kforce, was the CEO until he retired effective December 30, 2021. As such, Mr. Dunkel is reflected in the table as the PEO for 2020 and 2021. Mr. Liberatore was promoted to CEO effective January 1, 2022, and is reflected in the table as the PEO for 2022.For 2020 and 2021, the non-PEO NEOs include: Ms. Mitchell and Messrs. Liberatore, Kelly and Thomas. For 2022, the non-PEO NEOs include: Ms. Mitchell and Messrs. Kelly, Thomas and Hackman. | | | |
| PEO Total Compensation Amount | $ 2,800,004 | $ 3,200,009 | $ 3,374,987 | |
| PEO Actually Paid Compensation Amount | $ (505,552) | 8,712,014 | 3,799,834 | |
| Adjustment To PEO Compensation, Footnote [Text Block] | For the unvested stock awards included in CAP for both the PEO and non-PEO NEOs, we used the closing stock price on the last trading day of each fiscal year, less the closing stock price on the last trading day in the immediately preceding fiscal year to obtain the incremental value of the unvested stock awards. The closing stock price used in this analysis were as follows: $54.83 for December 30, 2022; $73.78 for December 31, 2021; $40.64 for December 31, 2020; and $37.46 for December 31, 2019.For the vested awards included in CAP for both the PEO and non-PEO NEOs, we used the closing stock price on the vesting date, less the closing stock price on the last trading day in the immediately preceding fiscal year.Adjusted Net Income for 2022 was $87 million which we believe is better aligned to our operational results. Refer to Appendix B - Adjusted Financial Performance Measures for more details. The following tables reconciles the amount disclosed in our SCT to the amount disclosed for CAP for the PEO and non-PEO NEOs: PEO Reconciliation: Year SCT Total Deductions from SCT table (1) (3) Additions to SCT Table (2) (3) CAP 2022 $ 5,564,913 $ (2,992,559) $ (505,552) $ 2,066,802 2021 $ 6,329,950 $ (3,529,950) $ 8,886,235 $ 11,686,235 2020 $ 6,653,318 $ (4,823,041) $ 5,092,168 $ 6,922,445 The following table provides the equity values included in the PEO and non-PEO NEO reconciliation tables above: PEO Equity Component of CAP: Year Fair Value of Current Year Equity Awards at 12/31/2022 Change in Fair Value of Prior Years' Awards That Remain Unvested at 12/31/2022 Change in Fair Value of Prior Years' Awards That Vested in 2022 Equity Value 2022 $ 2,800,004 $ (2,106,837) $ (1,198,719) $ (505,552) 2021 $ 3,200,009 $ 2,608,988 $ 2,903,017 $ 8,712,014 2020 $ 3,374,987 $ 189,740 $ 235,107 $ 3,799,834 | | | |
| Non-PEO NEO Average Total Compensation Amount | $ 688,117 | 2,064,996 | 1,458,111 | |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ (470,362) | $ 5,457,368 | $ 1,720,839 | |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Average non-PEO NEOs Reconciliation: Year SCT Total Deductions from SCT table (1) (3) Additions to SCT Table (2) (3) CAP 2022 $ 1,982,332 $ (756,924) $ (470,362) $ 754,954 2021 $ 3,629,803 $ (2,161,178) $ 5,457,368 $ 6,925,993 2020 $ 2,844,349 $ (1,868,230) $ 2,034,777 $ 3,010,896 (1) Represents the grant date fair value of equity-based awards granted each year, the value of dividends on unvested equity-based awards and the change in pension value (see footnote 3 to this table). (2) Reflects the impact of fluctuations in Kforce’s stock price on vested and unvested equity awards pursuant to the SEC’s methodology for determining CAP for each year shown. (3) The PEO table reflects both a deduction and an addition related to the change in pension value of $174,221 and $1,292,334 for 2020 and 2021, respectively. The non-PEO table reflects both a deduction and an addition related to the change in pension value of $313,938 for 2020. Average Non-PEO NEO’s Equity Component of CAP: Year Fair Value of Current Year Equity Awards at 12/31/2022 Change in Fair Value of Prior Years' Awards That Remain Unvested at 12/31/2022 Change in Fair Value of Prior Years' Awards That Vested in 2022 Equity Value 2022 $ 688,117 $ (630,923) $ (527,556) $ (470,362) 2021 $ 2,064,996 $ 2,002,501 $ 1,389,871 $ 5,457,368 2020 $ 1,458,111 $ 154,405 $ 108,323 $ 1,720,839 | | | |
| Total Shareholder Return Vs Peer Group [Text Block] | The amounts reflect the TSR for our respective peer group in that fiscal year. For more details on the changes in our 2022 peer group (as compared to our 2021 peer group), refer to our 2022 Proxy Statement filed with the SEC on March 11, 2022. The Peer Group TSR for each of our 2022 and 2021 peer groups (as if no change was made) would have been: 2022 2021 2020 2022 Peer Group $ 121 $ 152 $ 100 2021 Peer Group $ 119 $ 150 $ 99 | | | |
| Tabular List [Table Text Block] | 2022 2021 2020 2022 Peer Group $ 121 $ 152 $ 100 2021 Peer Group $ 119 $ 150 $ 99 Most Important Performance Measures • Revenue (and implied revenue growth) • Adjusted Diluted EPS (and implied EPS growth) • 3 Year Relative TSR | | | |
| PEO Name | Mr. Liberatore | Mr. Dunkel | | |
| Revenue Metric, Closing Stock Price, Per Share | $ 54.83 | $ 73.78 | $ 40.64 | $ 37.46 |
| Adjusted Net Income | $ 87,000,000 | | | |
| Measure [Axis]: 1 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | •Revenue (and implied revenue growth) | | | |
| Measure [Axis]: 2 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | •Adjusted Diluted EPS (and implied EPS growth) | | | |
| Measure [Axis]: 3 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Measure Name | •3 Year Relative TSR | | | |
| Mr. Liberatore [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| PEO Total Compensation Amount | $ 5,564,913 | | | |
| PEO Actually Paid Compensation Amount | 2,066,802 | | | |
| Non-PEO NEO Average Total Compensation Amount | 1,982,332 | | | |
| Non-PEO NEO Average Compensation Actually Paid Amount | 754,954,000 | | | |
| Total Shareholder Return Amount | 146 | | | |
| Peer Group Total Shareholder Return Amount | 121 | | | |
| Net Income (Loss) | $ 75,000,000 | | | |
| Company Selected Measure Amount | 1,711,000,000 | | | |
| Mr. Liberatore [Member] | Measure [Axis]: 2022 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Peer Group Total Shareholder Return, Adjusted Amount | $ 121 | | | |
| Mr. Liberatore [Member] | Adusted, Peer Group Total Shareholder Return Amount [Member] | Measure [Axis]: 2022 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Peer Group Total Shareholder Return, Adjusted Amount | | $ 152 | $ 100 | |
| Mr. Dunkel [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| PEO Total Compensation Amount | | 6,329,950 | 6,653,318 | |
| PEO Actually Paid Compensation Amount | | 11,686,235,000 | 6,922,445,000 | |
| Non-PEO NEO Average Total Compensation Amount | | 3,629,803 | 2,844,349 | |
| Non-PEO NEO Average Compensation Actually Paid Amount | | 6,925,993,000 | 3,010,896,000 | |
| Total Shareholder Return Amount | | 197 | 108 | |
| Peer Group Total Shareholder Return Amount | | 150 | 99 | |
| Net Income (Loss) | | $ 75,000,000 | $ 56,000,000 | |
| Company Selected Measure Amount | | 1,580,000,000 | 1,398,000,000 | |
| Mr. Dunkel [Member] | Adusted, Peer Group Total Shareholder Return Amount [Member] | Measure [Axis]: 2021 | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Peer Group Total Shareholder Return, Adjusted Amount | 119 | $ 150 | $ 99 | |
| PEO [Member] | Adjustment, Deductions [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (2,992,559) | (3,529,950) | (4,823,041) | |
| PEO [Member] | Adjustment, Additions [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (505,552) | 8,886,235 | 5,092,168 | |
| PEO [Member] | Adjustment, Equity Awards Reported Value [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (2,106,837) | 2,608,988 | 189,740 | |
| PEO [Member] | Adjustment, Equity Award Adjustments [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (1,198,719) | 2,903,017 | 235,107 | |
| PEO [Member] | Mr. Dunkel [Member] | Adjustment, Exclusion of Change in Pension Value [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | | 1,292,334 | 174,221 | |
| Non-PEO NEO [Member] | Adjustment, Deductions [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (756,924) | (2,161,178) | (1,868,230) | |
| Non-PEO NEO [Member] | Adjustment, Additions [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (470,362) | 5,457,368 | 2,034,777 | |
| Non-PEO NEO [Member] | Adjustment, Equity Awards Reported Value [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | (630,923) | 2,002,501 | 154,405 | |
| Non-PEO NEO [Member] | Adjustment, Equity Award Adjustments [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | $ (527,556) | $ 1,389,871 | 108,323 | |
| Non-PEO NEO [Member] | Mr. Dunkel [Member] | Adjustment, Exclusion of Change in Pension Value [Member] | | | | |
| Pay vs Performance Disclosure [Table] | | | | |
| Adjustment to Compensation Amount | | | $ 313,938 | |
