| Cover | 12 Months Ended |
| Dec. 31, 2022 | |
| Document Information [Line Items] | |
| Document Type | DEF 14A |
| Amendment Flag | false |
| Entity Information [Line Items] | |
| Entity Registrant Name | ICF INTERNATIONAL, INC. |
| Entity Central Index Key | 0001362004 |
| Pay vs Performance Disclosure | 12 Months Ended | ||
| Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | |
| Pay vs Performance Disclosure [Table] | |||
| Pay vs Performance [Table Text Block] | PAY vs. PERFORMANCE The following disclosures are being provided in accordance with final rules adopted by the SEC, on August 2, 2022, pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010. Certain measures disclosed in the table below, including “Compensation Actually Paid,” are calculated in accordance with those rules. However, these rules were issued subsequent to the Human Capital Committee’s executive compensation determinations for 2022. Accordingly, the Human Capital Committee did not necessarily consider these measures (except with respect to Non-GAAP EPS) or these calculations in setting compensation for the named executive officers or for linking executive compensation with Company performance for 2022 or any prior periods disclosed below. For a description of the Human Capital Committee’s processes, policies and considerations when setting compensation and evaluating performance, please see the “Compensation Discussion and Analysis” beginning on page 50 of this proxy statement. Year (a) Summary Compensation Table Total for Compensation Actually Paid to Average Summary Compensation Table Total for Non-CEO NEOs¹ ($) (d) Average Compensation Actually Paid to Non-CEO NEOs ¹ , ($) (e) Value of Initial Fixed $100 Investment based on:4 Non-GAAP EPS 5 (i) CEO¹ ($) (b) CEO¹ , , ($) (c) TSR ($) (f) Peer Group TSR ($) (g) Net Income ($ Millions) 2022 $ 4,848,381 $ 3,370,042 $ 1,462,435 $ 1,077,211 $ 110 $ 135 $ 64 $ 5.77 2021 $ 4,398,947 $ 4,234,738 $ 1,351,755 $ 1,329,197 $ 114 $ 149 $ 71 $ 4.82 2020 $ 3,007,891 $ 1,944,332 $ 2,330,360 $ 2,038,317 $ 82 $ 118 $ 55 $ 4.17 1. John Wasson was our CEO for the years presented in this table. The individuals comprising Non-CEO 2020 2021 2022 Sudhakar Kesavan James C. Morgan James C. Morgan James C. Morgan Bettina Welsh Bettina Welsh Bettina Welsh Sergio Ostria Barry Broadus Sergio Ostria Mark Lee Anne Choate Mark Lee 2. Compensation Actually Paid reflects the exclusions and inclusions Non-CEO Year Summary Compensation Table Total for John Wasson ($) Exclusion of Stock Awards and Option Awards for John Wasson ($) Inclusion of Equity Values for John Wasson ($) Compensation Actually Paid to John Wasson ($) 2022 $ 4,848,381 $ (2,744,047) $ 1,265,708 $ 3,370,042 2021 $ 4,398,947 $ (2,324,936) $ 2,160,727 $ 4,234,738 2020 $ 3,007,891 $ (1,434,943) $ 371,385 $ 1,944,332 Year Average Summary Compensation Table Total for Non-CEO ($) Average Exclusion of Stock Awards and Option Awards for Non-CEO ($) Average Inclusion of Equity Values for Non-CEO NEOs ($) Average Compensation Actually Paid to Non-CEO ($) 2022 $ 1,462,435 $ (582,745) $ 197,522 $ 1,077,211 2021 $ 1,351,755 $ (506,439 $ 483,881 $ 1,329,197 2020 $ 2,330,360 $ (828,283 $ 536,239 $ 2,038,317 The amounts in the Inclusion of Equity Values in the tables above are derived from the amounts set forth in the following tables: Year Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for John Wasson ($) Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for John Wasson ($) Vesting-Date Fair Value of Equity Awards Granted During Year that Vested During Year for John Wasson ($) Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for John Wasson ($) Total - Inclusion of Equity Values for Wasson ($) 2022 1,465,955 97,527 0 (297,773 ) 1,265,708 2021 1,415,301 499,795 0 245,632 2,160,727 2020 866,524 (141,032 ) 0 (354,107 ) 371,385 Year Average Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for Non-CEO NEOs ($) Average Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for Non-CEO ($) Average Vesting- Date Fair Value of Equity Awards Granted During Year that Vested During Year for Non-CEO ($) Average Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for Non-CEO ($) Total - Average Inclusion of Equity Values for Non-CEO ($) 2022 234,521 15,316 0 (52,315 ) 197,522 2021 308,294 124,198 0 51,389 483,881 2020 500,177 (98,570 ) 420,559 (285,927 ) 536,239 4. The amounts set forth under the heading “Peer Group TSR” reflect the value, as of the end of the applicable fiscal year, of a hypothetical initial investment of $100 made on December 31, 2019, into the S&P Composite 1500 – Commercial & Professional Services Index. 5. The Human Capital Committee determined that Non-GAAP Non-CEO non-GAAP | ||
| Company Selected Measure Name | Non-GAAP EPS | ||
| Named Executive Officers, Footnote [Text Block] | 1. John Wasson was our CEO for the years presented in this table. The individuals comprising Non-CEO 2020 2021 2022 Sudhakar Kesavan James C. Morgan James C. Morgan James C. Morgan Bettina Welsh Bettina Welsh Bettina Welsh Sergio Ostria Barry Broadus Sergio Ostria Mark Lee Anne Choate Mark Lee | ||
| Peer Group Issuers, Footnote [Text Block] | The amounts set forth under the heading “Peer Group TSR” reflect the value, as of the end of the applicable fiscal year, of a hypothetical initial investment of $100 made on December 31, 2019, into the S&P Composite 1500 – Commercial & Professional Services Index. | ||
| PEO Total Compensation Amount | $ 4,848,381 | $ 4,398,947 | $ 3,007,891 |
| PEO Actually Paid Compensation Amount | $ 3,370,042 | 4,234,738 | 1,944,332 |
| Adjustment To PEO Compensation, Footnote [Text Block] | Year Summary Compensation Table Total for John Wasson ($) Exclusion of Stock Awards and Option Awards for John Wasson ($) Inclusion of Equity Values for John Wasson ($) Compensation Actually Paid to John Wasson ($) 2022 $ 4,848,381 $ (2,744,047) $ 1,265,708 $ 3,370,042 2021 $ 4,398,947 $ (2,324,936) $ 2,160,727 $ 4,234,738 2020 $ 3,007,891 $ (1,434,943) $ 371,385 $ 1,944,332 The amounts in the Inclusion of Equity Values in the tables above are derived from the amounts set forth in the following tables: Year Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for John Wasson ($) Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for John Wasson ($) Vesting-Date Fair Value of Equity Awards Granted During Year that Vested During Year for John Wasson ($) Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for John Wasson ($) Total - Inclusion of Equity Values for Wasson ($) 2022 1,465,955 97,527 0 (297,773 ) 1,265,708 2021 1,415,301 499,795 0 245,632 2,160,727 2020 866,524 (141,032 ) 0 (354,107 ) 371,385 | ||
| Non-PEO NEO Average Total Compensation Amount | $ 1,462,435 | 1,351,755 | 2,330,360 |
| Non-PEO NEO Average Compensation Actually Paid Amount | $ 1,077,211 | 1,329,197 | 2,038,317 |
| Adjustment to Non-PEO NEO Compensation Footnote [Text Block] | Year Average Summary Compensation Table Total for Non-CEO ($) Average Exclusion of Stock Awards and Option Awards for Non-CEO ($) Average Inclusion of Equity Values for Non-CEO NEOs ($) Average Compensation Actually Paid to Non-CEO ($) 2022 $ 1,462,435 $ (582,745) $ 197,522 $ 1,077,211 2021 $ 1,351,755 $ (506,439 $ 483,881 $ 1,329,197 2020 $ 2,330,360 $ (828,283 $ 536,239 $ 2,038,317 Year Average Year-End Fair Value of Equity Awards Granted During Year That Remained Unvested as of Last Day of Year for Non-CEO NEOs ($) Average Change in Fair Value from Last Day of Prior Year to Last Day of Year of Unvested Equity Awards for Non-CEO ($) Average Vesting- Date Fair Value of Equity Awards Granted During Year that Vested During Year for Non-CEO ($) Average Change in Fair Value from Last Day of Prior Year to Vesting Date of Unvested Equity Awards that Vested During Year for Non-CEO ($) Total - Average Inclusion of Equity Values for Non-CEO ($) 2022 234,521 15,316 0 (52,315 ) 197,522 2021 308,294 124,198 0 51,389 483,881 2020 500,177 (98,570 ) 420,559 (285,927 ) 536,239 | ||
| Compensation Actually Paid vs. Total Shareholder Return [Text Block] | Description of Relationship Between CEO and Other Non-CEO The following chart sets forth the relationship between Compensation Actually Paid to our CEO, the average of Compensation Actually Paid to our other Non-CEO | ||
| Compensation Actually Paid vs. Net Income [Text Block] | Description of Relationship Between CEO and Other Non-CEO The following chart sets forth the relationship between Compensation Actually Paid to our CEO, the average of Compensation Actually Paid to our Non-CEO | ||
| Compensation Actually Paid vs. Company Selected Measure [Text Block] | Description of Relationship Between CEO and Other Non-CEO The following chart sets forth the relationship between Compensation Actually Paid to our CEO, the average of Compensation Actually Paid to our Non-CEO | ||
| Total Shareholder Return Vs Peer Group [Text Block] | Description of Relationship Between Company TSR and Peer Group TSR The following chart compares our cumulative TSR over the three most recently completed fiscal years to that of the S&P Composite 1500 – Commercial & Professional Services Index over the same period. | ||
| Tabular List [Table Text Block] | Tabular List of Most Important Financial Performance Measures The following table presents the financial performance measures that the Company considers to have been the most important in linking Compensation Actually Paid to our CEO and Non-CEO Non-GAAP EPS Gross Revenue Relative Total Shareholder Return | ||
| Total Shareholder Return Amount | $ 110 | 114 | 82 |
| Peer Group Total Shareholder Return Amount | 135 | 149 | 118 |
| Net Income (Loss) | $ 64,000,000 | $ 71,000,000 | $ 55,000,000 |
| Company Selected Measure Amount | 5.77 | 4.82 | 4.17 |
| PEO Name | John Wasson | ||
| Measure [Axis]: 1 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Non-GAAP EPS | ||
| Non-GAAP Measure Description [Text Block] | The Human Capital Committee determined that Non-GAAP Non-CEO non-GAAP | ||
| Measure [Axis]: 2 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Gross Revenue | ||
| Measure [Axis]: 3 | |||
| Pay vs Performance Disclosure [Table] | |||
| Measure Name | Relative Total Shareholder Return | ||
| PEO [Member] | Exclusion Of Stock Awards And Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (2,744,047) | $ (2,324,936) | $ (1,434,943) |
| PEO [Member] | Total Inclusion Of Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 1,265,708 | 2,160,727 | 371,385 |
| PEO [Member] | Year End Fair Value Of Equity Awards Granted During Year That Remained Unvested As Of Last Day Of Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 1,465,955 | 1,415,301 | 866,524 |
| PEO [Member] | Change In Fair Value From Last Day Of Prior Year To Last Day Of Year Of Unvested Equity Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 97,527 | 499,795 | (141,032) |
| PEO [Member] | Vesting Date Fair Value Of Equity Awards Granted During Year That Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 0 |
| PEO [Member] | Change In Fair Value From Last Day Of Prior Year To Vesting Date Of Unvested Equity Awards That Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (297,773) | 245,632 | (354,107) |
| Non-PEO NEO [Member] | Exclusion Of Stock Awards And Option Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | (582,745) | (506,439) | (828,283) |
| Non-PEO NEO [Member] | Total Inclusion Of Equity Values [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 197,522 | 483,881 | 536,239 |
| Non-PEO NEO [Member] | Year End Fair Value Of Equity Awards Granted During Year That Remained Unvested As Of Last Day Of Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 234,521 | 308,294 | 500,177 |
| Non-PEO NEO [Member] | Change In Fair Value From Last Day Of Prior Year To Last Day Of Year Of Unvested Equity Awards [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 15,316 | 124,198 | (98,570) |
| Non-PEO NEO [Member] | Vesting Date Fair Value Of Equity Awards Granted During Year That Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | 0 | 0 | 420,559 |
| Non-PEO NEO [Member] | Change In Fair Value From Last Day Of Prior Year To Vesting Date Of Unvested Equity Awards That Vested During Year [Member] | |||
| Pay vs Performance Disclosure [Table] | |||
| Adjustment to Compensation Amount | $ (52,315) | $ 51,389 | $ (285,927) |
