Basis of Presentation (Policies)	9 Months Ended
Sep. 30, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary	Summary The accompanying unaudited interim consolidated financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") pertaining to reports on Form 10-Q and should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, as amended. Accordingly, the accompanying unaudited interim consolidated financial statements do not include all of the information and footnotes required by U.S. generally accepted accounting principles ("U.S. GAAP") for complete financial statements. In the opinion of management, these statements include all adjustments (consisting only of normal, recurring adjustments) necessary for a fair presentation of the consolidated financial statements. The consolidated financial statements include the accounts of Hill and its wholly and majority-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The interim operating results are not necessarily indicative of the results for a full year. NEYO Group Acquisition On June 30, 2021, the Company acquired all of the equity interests of NEYO Group, a 120-person firm specializing in cost management and estimating support and also providing project management, project monitoring, and other services. NEYO maintains offices in Bangalore, Chennai, Delhi, and Mumbai, as well as project offices in Hyderabad, Pune, and Kolkata.
Foreign Currency Translations and Transactions	Foreign Currency Translations and TransactionsAssets and liabilities of all foreign operations are translated at period-end rates of exchange while revenues and expenses are translated at the average monthly exchange rates. Gains or losses resulting from translating foreign currency financial statements are accumulated in a separate component of stockholders’ equity titled accumulated other comprehensive income (loss) until the entity is sold or substantially liquidated. Gains or losses arising from foreign currency transactions (transactions denominated in a currency other than the entity’s local currency), including those resulting from intercompany transactions, are reflected in the Company's consolidated statements of operations. The impact of foreign exchange on long-term intercompany loans, for which repayment has not been scheduled or planned and permanent equity has been elected, are recorded in accumulated other comprehensive income (loss) on the Company's consolidated balance sheets.
Concentrations of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash equivalents and accounts receivable. The Company maintains its cash accounts with high quality financial institutions. Although the Company believes that the financial institutions with which it does business will be able to fulfill their commitments, there is no assurance that those institutions will be able to continue to do so.
Allowance for Doubtful Accounts	Allowance for Doubtful AccountsThe allowance for doubtful accounts is an estimate prepared by management based on identification of the collectability of specific accounts and the overall condition of the receivable portfolios. When evaluating the adequacy of the allowance for doubtful accounts, the Company specifically analyzes trade receivables, including retainage receivable, historical bad debts, client credits, client concentrations, current economic trends and changes in client payment terms. If the financial condition of clients were to deteriorate, resulting in an impairment of their ability to make payments, additional allowances may be required. Likewise, should the Company determine that it would be able to realize more of its receivables in the future than previously estimated, an adjustment to the allowance would increase earnings in the period such determination was made. The allowance for doubtful accounts is reviewed on a quarterly basis and adjustments are recorded as deemed necessary.
Retainage Receivable and Revenue Recognition	Retainage ReceivableRetainage receivable represents balances billed but not paid by clients pursuant to retainage provisions in certain contracts and will be due upon completion of specific tasks or the completion of the contract.Revenue Recognition The Company generates revenue primarily from providing professional services to its clients under various types of contracts. In providing these services, the Company may incur reimbursable expenses, which consist principally of amounts paid to subcontractors and other third parties and travel and other job related expenses that are contractually reimbursable from clients. The Company includes reimbursable expenses in computing and reporting its total revenue as long as the Company remains responsible to the client for the fulfillment of the contract and for the overall acceptability of all services provided. If estimated total costs on any contract project a loss, the Company charges the entire estimated loss to operations in the period the loss becomes known. The cumulative effect of revisions to revenue, estimated costs to complete contracts, including penalties, incentive awards, change orders, claims, anticipated losses, and others are recorded in the accounting period in which the events indicating a loss are known and the loss can be reasonably estimated. These loss projects are re-assessed for each subsequent reporting period until the project is complete. Such revisions could occur at any time, and the effects may be material.
Income Taxes	Income Taxes The Company estimates income taxes in each of the jurisdictions in which it operates. This process involves estimating its actual current tax exposure together with assessing temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included within the Company’s consolidated balance sheets. The Company assesses the likelihood that the deferred tax assets will be recovered from future taxable income and to the extent it believes recovery is not likely, the Company establishes a valuation allowance. To the extent the Company establishes a valuation allowance in a period, it must include an expense within the tax provision in the consolidated statements of operations. The Company has recorded a valuation allowance to reduce the deferred income tax assets to an amount that is more likely than not to be realized in future years. If the Company determines in the future that it is “more likely than not” (i.e., a likelihood greater than 50 percent) to be allowed by the tax jurisdiction based solely on the technical merits of the position, that the deferred tax assets subject to the valuation allowance will be realized, then the previously provided valuation allowance will be adjusted. The Company recognizes a tax benefit in the financial statements for an uncertain tax position only if management’s assessment is that the position is more likely than not that the benefit will be ultimately realized. The term “tax position” refers to a position in a previously filed tax return or a position expected to be taken in a future tax return that is reflected in measuring current or deferred income tax assets and liabilities for interim or annual periods.
Restricted Cash	Restricted CashRestricted cash primarily represents cash collateral required to be maintained in foreign bank accounts to serve as collateral for letters of credit, bonds or guarantees on certain projects. The cash will remain restricted until the respective project has been completed, which typically is greater than one year.
Earnings (loss) per Share	Earnings (loss) per ShareBasic earnings (loss) per common share have been computed using the weighted-average number of shares of common stock outstanding during the period. Diluted earnings (loss) per common share incorporates the incremental shares issuable upon the assumed exercise of stock options and the assumed vesting of stock and deferred and restricted stock unit awards using the treasury stock method, if dilutive.
New Accounting Pronouncements	New Accounting PronouncementsChanges to U.S. GAAP are typically established by the Financial Accounting Standards Board (“FASB”) in the form of accounting standards updates (“ASUs”) to the FASB’s Accounting Standards Codification (“ASC”). The Company considers the applicability and impact of all ASUs and, based on its assessment, determined that any recently issued or proposed ASUs not listed below are either not applicable to the Company or adoption will have minimal impact on its consolidated financial statements.For additional information with respect to new accounting pronouncements and the impact of these pronouncements on our consolidated financial statements, see Note 3 to the consolidated financial statements in Item 8 of Form 10-K for the year ended December 31, 2021 filed with the SEC on March 31, 2022, as amended.

Basis of Presentation (Policies)

9 Months Ended

Sep. 30, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The accompanying unaudited interim consolidated financial statements were prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") pertaining to reports on Form 10-Q and should be read in conjunction with the consolidated financial statements and accompanying notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2021, as amended. Accordingly, the accompanying unaudited interim consolidated financial statements do not include all of the information and footnotes required by U.S. generally accepted accounting principles ("U.S. GAAP") for complete financial statements. In the opinion of management, these statements include all adjustments (consisting only of normal, recurring adjustments) necessary for a fair presentation of the consolidated financial statements. The consolidated financial statements include the accounts of Hill and its wholly and majority-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The interim operating results are not necessarily indicative of the results for a full year.

NEYO Group Acquisition

On June 30, 2021, the Company acquired all of the equity interests of NEYO Group, a 120-person firm specializing in cost management and estimating support and also providing project management, project monitoring, and other services. NEYO maintains offices in Bangalore, Chennai, Delhi, and Mumbai, as well as project offices in Hyderabad, Pune, and Kolkata.

Foreign Currency Translations and Transactions

Foreign Currency Translations and TransactionsAssets and liabilities of all foreign operations are translated at period-end rates of exchange while revenues and expenses are translated at the average monthly exchange rates. Gains or losses resulting from translating foreign currency financial statements are accumulated in a separate component of stockholders’ equity titled accumulated other comprehensive income (loss) until the entity is sold or substantially liquidated. Gains or losses arising from foreign currency transactions (transactions denominated in a currency other than the entity’s local currency), including those resulting from intercompany transactions, are reflected in the Company's consolidated statements of operations. The impact of foreign exchange on long-term intercompany loans, for which repayment has not been scheduled or planned and permanent equity has been elected, are recorded in accumulated other comprehensive income (loss) on the Company's consolidated balance sheets.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of cash equivalents and accounts receivable.

The Company maintains its cash accounts with high quality financial institutions. Although the Company believes that the financial institutions with which it does business will be able to fulfill their commitments, there is no assurance that those institutions will be able to continue to do so.

Allowance for Doubtful Accounts

Allowance for Doubtful AccountsThe allowance for doubtful accounts is an estimate prepared by management based on identification of the collectability of specific accounts and the overall condition of the receivable portfolios. When evaluating the adequacy of the allowance for doubtful accounts, the Company specifically analyzes trade receivables, including retainage receivable, historical bad debts, client credits, client concentrations, current economic trends and changes in client payment terms. If the financial condition of clients were to deteriorate, resulting in an impairment of their ability to make payments, additional allowances may be required. Likewise, should the Company determine that it would be able to realize more of its receivables in the future than previously estimated, an adjustment to the allowance would increase earnings in the period such determination was made. The allowance for doubtful accounts is reviewed on a quarterly basis and adjustments are recorded as deemed necessary.

Retainage Receivable and Revenue Recognition

Retainage ReceivableRetainage receivable represents balances billed but not paid by clients pursuant to retainage provisions in certain contracts and will be due upon completion of specific tasks or the completion of the contract.Revenue Recognition

The Company generates revenue primarily from providing professional services to its clients under various types of contracts. In providing these services, the Company may incur reimbursable expenses, which consist principally of amounts paid to subcontractors and other third parties and travel and other job related expenses that are contractually reimbursable from clients. The Company includes reimbursable expenses in computing and reporting its total revenue as long as the Company remains responsible to the client for the fulfillment of the contract and for the overall acceptability of all services provided.

If estimated total costs on any contract project a loss, the Company charges the entire estimated loss to operations in the period the loss becomes known. The cumulative effect of revisions to revenue, estimated costs to complete contracts, including penalties, incentive awards, change orders, claims, anticipated losses, and others are recorded in the accounting period in which the events indicating a loss are known and the loss can be reasonably estimated. These loss projects are re-assessed for each subsequent reporting period until the project is complete. Such revisions could occur at any time, and the effects may be material.

Income Taxes

The Company estimates income taxes in each of the jurisdictions in which it operates. This process involves estimating its actual current tax exposure together with assessing temporary differences resulting from differing treatment of items for tax and accounting purposes. These differences result in deferred tax assets and liabilities, which are included within the Company’s consolidated balance sheets. The Company assesses the likelihood that the deferred tax assets will be recovered from future taxable income and to the extent it believes recovery is not likely, the Company establishes a valuation allowance. To the extent the Company establishes a valuation allowance in a period, it must include an expense within the tax provision in the consolidated statements of operations. The Company has recorded a valuation allowance to reduce the deferred income tax assets to an amount that is more likely than not to be realized in future years. If the Company determines in the future that it is “more likely than not” (i.e., a likelihood greater than 50 percent) to be allowed by the tax jurisdiction based solely on the technical merits of the position, that the deferred tax assets subject to the valuation allowance will be realized, then the previously provided valuation allowance will be adjusted.

The Company recognizes a tax benefit in the financial statements for an uncertain tax position only if management’s assessment is that the position is more likely than not that the benefit will be ultimately realized. The term “tax position” refers to a position in a previously filed tax return or a position expected to be taken in a future tax return that is reflected in measuring current or deferred income tax assets and liabilities for interim or annual periods.

Restricted Cash

Restricted CashRestricted cash primarily represents cash collateral required to be maintained in foreign bank accounts to serve as collateral for letters of credit, bonds or guarantees on certain projects. The cash will remain restricted until the respective project has been completed, which typically is greater than one year.

Earnings (loss) per Share

Earnings (loss) per ShareBasic earnings (loss) per common share have been computed using the weighted-average number of shares of common stock outstanding during the period. Diluted earnings (loss) per common share incorporates the incremental shares issuable upon the assumed exercise of stock options and the assumed vesting of stock and deferred and restricted stock unit awards using the treasury stock method, if dilutive.

New Accounting Pronouncements

New Accounting PronouncementsChanges to U.S. GAAP are typically established by the Financial Accounting Standards Board (“FASB”) in the form of accounting standards updates (“ASUs”) to the FASB’s Accounting Standards Codification (“ASC”). The Company considers the applicability and impact of all ASUs and, based on its assessment, determined that any recently issued or proposed ASUs not listed below are either not applicable to the Company or adoption will have minimal impact on its consolidated financial statements.For additional information with respect to new accounting pronouncements and the impact of these pronouncements on our consolidated financial statements, see Note 3 to the consolidated financial statements in Item 8 of Form 10-K for the year ended December 31, 2021 filed with the SEC on March 31, 2022, as amended.