Cover
Cover - USD ($) | 12 Months Ended | ||
Dec. 31, 2021 | Mar. 08, 2022 | Jun. 30, 2021 | |
Cover [Abstract] | |||
Document Type | 10-K/A | ||
Amendment Flag | false | ||
Document Annual Report | true | ||
Document Transition Report | false | ||
Document Period End Date | Dec. 31, 2021 | ||
Document Fiscal Period Focus | FY | ||
Document Fiscal Year Focus | 2021 | ||
Current Fiscal Year End Date | --12-31 | ||
Entity File Number | 001-33961 | ||
Entity Registrant Name | HILL INTERNATIONAL, INC. | ||
Entity Central Index Key | 0001287808 | ||
Entity Tax Identification Number | 20-0953973 | ||
Entity Incorporation, State or Country Code | DE | ||
Entity Address, Address Line One | One Commerce Square | ||
Entity Address, Address Line Two | 2005 Market Street, 17th Floor | ||
Entity Address, City or Town | Philadelphia | ||
Entity Address, State or Province | PA | ||
Entity Address, Postal Zip Code | 19103 | ||
City Area Code | 215 | ||
Local Phone Number | 309-7700 | ||
Title of 12(b) Security | Common stock, par value $0.0001 per share | ||
Trading Symbol | HIL | ||
Security Exchange Name | NYSE | ||
Entity Well-known Seasoned Issuer | No | ||
Entity Voluntary Filers | No | ||
Entity Current Reporting Status | Yes | ||
Entity Interactive Data Current | Yes | ||
Entity Filer Category | Accelerated Filer | ||
Entity Small Business | true | ||
Entity Emerging Growth Company | false | ||
Entity Shell Company | false | ||
Entity Public Float | $ 120,074,446 | ||
Entity Common Stock, Shares Outstanding | 57,142,744 | ||
ICFR Auditor Attestation Flag | true | ||
Auditor Name | Grant Thornton LLP | ||
Auditor Firm ID | 248 | ||
Auditor Location | Philadelphia, PA |