Liquidity (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Nov. 30, 2022	Oct. 31, 2022	Sep. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Liquidity [Line Items]
Cash and cash equivalents				$ 22,834		$ 21,821
Payment of amendment fee					$ 463
Total notes payable and long-term debt, gross				60,334		55,443
Hill International, Inc. - Société Générale 2017 Term Loan Facility
Liquidity [Line Items]
Reduction to credit commitments, amount				500
Hill International, Inc. - Société Générale 2017 Term Loan Facility | Forecast
Liquidity [Line Items]
Reduction to credit commitments, amount	$ 3,000	$ 500	$ 500
U.S. Revolver | Letters of credit
Liquidity [Line Items]
Available borrowing capacity				7		2,643
Amounts outstanding				$ 4,972		6,457
U.S. Revolver | Hill International, Inc. - Société Générale Domestic Revolving Credit Facility
Liquidity [Line Items]
Line of credit, interest rate increase (percent)					1.10%
International Revolver | Hill International N.V.. - Société Générale International Revolving Credit Facility
Liquidity [Line Items]
Line of credit, interest rate increase (percent)				1.50%
Secured Debt | Hill International, Inc. - Société Générale Domestic Revolving Credit Facility
Liquidity [Line Items]
Total notes payable and long-term debt, gross				$ 23,303		19,400
Secured Debt | Hill International N.V.. - Société Générale International Revolving Credit Facility
Liquidity [Line Items]
Total notes payable and long-term debt, gross				4,884		5,802
Secured Debt | Hill International, Inc. - Société Générale 2017 Term Loan Facility
Liquidity [Line Items]
Line of credit, interest rate increase (percent)					1.00%
Total notes payable and long-term debt, gross				28,425		28,650
Foreign credit agreements | International Revolver | Revolving credit facility
Liquidity [Line Items]
Available borrowing capacity				3,436		5,980
Foreign credit agreements | Other Foreign Banks | U.S. Revolver | Revolving credit facility
Liquidity [Line Items]
Amounts outstanding				4,972
Foreign credit agreements | Other Foreign Banks | International Revolver | Revolving credit facility
Liquidity [Line Items]
Available borrowing capacity				175		520
Amounts outstanding				$ 509		$ 478