Basis of Presentation	6 Months Ended
Jun. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	1. Basis of presentation The unaudited condensed consolidated financial statements and notes herein should be read in conjunction with the audited consolidated financial statements of Great Lakes Dredge & Dock Corporation and Subsidiaries (the “Company” or “Great Lakes”) and the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. The condensed consolidated financial statements included herein have been prepared by the Company without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to the SEC’s rules and regulations. Management believes that the disclosures included herein are adequate and make the information presented not misleading. In the opinion of management, all adjustments, which are of a normal and recurring nature (except as otherwise noted), that are necessary to present fairly the Company’s financial position as of June 30, 2025 and December 31, 2024, and its results of operations for the three and six months ended June 30, 2025 and 2024 and cash flows for the six months ended June 30, 2025 and 2024 have been included. The components of costs of contract revenues include labor, equipment (including depreciation, maintenance, insurance and long-term rentals), subcontracts, fuel, supplies, short-term rentals and project overhead. Hourly labor is generally hired on a project-by-project basis. Costs of contract revenues vary significantly depending on the type and location of work performed and assets utilized. The Company has one operating segment which is also the Company’s reportable segment and reporting unit of which the Company tests goodwill for impairment. When conducting the annual impairment test for goodwill, the Company can choose to assess qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is below its carrying value. If a qualitative assessment determines an impairment is more likely than not, the Company is required to perform a quantitative impairment test. Otherwise, no further analysis is required. The Company also may elect to forego the qualitative and move directly to the quantitative impairment test. The Company performed its annual test of impairment as of July 1, 2024. The Company assessed qualitative factors for any indications of potential impairment of the reporting unit. Upon completing this assessment, it was determined that the fair value of the reporting unit is more likely than not greater than its carrying value as of the assessment date and, as a result, a quantitative test was not performed. The Company will continue to monitor for changes in facts or circumstances that may impact its estimates. The Company will perform its next scheduled annual impairment test of goodwill in the third quarter of 2025. On March 14, 2025, the Company announced that its board of directors approved a share repurchase program, authorizing, but not obligating, the repurchase of up to an aggregate amount of $50.0 million of its common stock from time to time through March 14, 2026. Of the approved amount under the share repurchase program, the Company repurchased 1,312,493 shares of common stock for approximately $11.6 million of common stock during the six months ended June 30, 2025. The condensed consolidated statements of operations and comprehensive income for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year. Recently Issued Accounting Pronouncements—In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2024-03, Disaggregation of Income Statement Expenses (“DISE”). The ASU primarily requires companies to disclose additional information about specific expense categories in the notes to financial statements at interim and annual reporting periods. The guidance will be applied on a prospective basis with the option to apply the standard retrospectively. The new guidance will be effective for the Company’s year ending December 31, 2027 and interim periods during the year ended December 31, 2028. Management is currently evaluating the impact of this guidance. In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740)” (“ASU 2023-09”). The amendments in ASU 2023-09 address investor requests for more transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. One of the amendments in ASU 2023-09 includes disclosure of, on an annual basis, a tabular rate reconciliation of (i) the reported income tax expense (or benefit) from continuing operations, to (ii) the product of the income (or loss) from continuing operations before income taxes and the applicable statutory federal income tax rate of the jurisdiction of domicile using specific categories, including separate disclosure for any reconciling items within certain categories that are equal to or greater than a specified quantitative threshold of 5%. ASU 2023-09 also requires disclosure of, on an annual basis, the year to date amount of income taxes paid (net of refunds received) disaggregated by federal, state, and foreign jurisdictions, including additional disaggregated information on income taxes paid (net of refunds received) to an individual jurisdiction equal to or greater than 5% of total income taxes paid (net of refunds received). The amendments in ASU 2023-09 are effective for annual periods beginning after December 15, 2024, and should be applied prospectively. The adoption of ASU 2023-09 is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures.

Basis of Presentation

6 Months Ended

Jun. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of presentation

The unaudited condensed consolidated financial statements and notes herein should be read in conjunction with the audited consolidated financial statements of Great Lakes Dredge & Dock Corporation and Subsidiaries (the “Company” or “Great Lakes”) and the notes thereto, included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024. The condensed consolidated financial statements included herein have been prepared by the Company without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) have been condensed or omitted pursuant to the SEC’s rules and regulations. Management believes that the disclosures included herein are adequate and make the information presented not misleading. In the opinion of management, all adjustments, which are of a normal and recurring nature (except as otherwise noted), that are necessary to present fairly the Company’s financial position as of June 30, 2025 and December 31, 2024, and its results of operations for the three and six months ended June 30, 2025 and 2024 and cash flows for the six months ended June 30, 2025 and 2024 have been included.

The components of costs of contract revenues include labor, equipment (including depreciation, maintenance, insurance and long-term rentals), subcontracts, fuel, supplies, short-term rentals and project overhead. Hourly labor is generally hired on a project-by-project basis. Costs of contract revenues vary significantly depending on the type and location of work performed and assets utilized.

The Company has one operating segment which is also the Company’s reportable segment and reporting unit of which the Company tests goodwill for impairment. When conducting the annual impairment test for goodwill, the Company can choose to assess qualitative factors to determine whether it is more likely than not that the fair value of the reporting unit is below its carrying value. If a qualitative assessment determines an impairment is more likely than not, the Company is required to perform a quantitative impairment test. Otherwise, no further analysis is required. The Company also may elect to forego the qualitative and move directly to the quantitative impairment test. The Company performed its annual test of impairment as of July 1, 2024. The Company assessed qualitative factors for any indications of potential impairment of the reporting unit. Upon completing this assessment, it was determined that the fair value of the reporting unit is more likely than not greater than its carrying value as of the assessment date and, as a result, a quantitative test was not performed. The Company will continue to monitor for changes in facts or circumstances that may impact its estimates. The Company will perform its next scheduled annual impairment test of goodwill in the third quarter of 2025.

On March 14, 2025, the Company announced that its board of directors approved a share repurchase program, authorizing, but not obligating, the repurchase of up to an aggregate amount of $50.0 million of its common stock from time to time through March 14, 2026. Of the approved amount under the share repurchase program, the Company repurchased 1,312,493 shares of common stock for approximately $11.6 million of common stock during the six months ended June 30, 2025.

The condensed consolidated statements of operations and comprehensive income for the interim periods presented herein are not necessarily indicative of the results to be expected for the full year.

Recently Issued Accounting Pronouncements—In November 2024, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2024-03, Disaggregation of Income Statement Expenses (“DISE”). The ASU primarily requires companies to disclose additional information about specific expense categories in the notes to financial statements at interim and annual reporting periods. The guidance will be applied on a prospective basis with the option to apply the standard retrospectively. The new guidance will be effective for the Company’s year ending December 31, 2027 and interim periods during the year ended December 31, 2028. Management is currently evaluating the impact of this guidance.

In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740)” (“ASU 2023-09”). The amendments in ASU 2023-09 address investor requests for more transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. One of the amendments in ASU 2023-09 includes disclosure of, on an annual basis, a tabular rate reconciliation of (i) the reported income tax expense (or benefit) from continuing operations, to (ii) the product of the income (or loss) from continuing operations before income taxes and the applicable statutory federal income tax rate of the jurisdiction of domicile using specific categories, including separate disclosure for any reconciling items within certain categories that are equal to or greater than a specified quantitative threshold of 5%. ASU 2023-09 also requires disclosure of, on an annual basis, the year to date amount of income taxes paid (net of refunds received) disaggregated by federal,

state, and foreign jurisdictions, including additional disaggregated information on income taxes paid (net of refunds received) to an individual jurisdiction equal to or greater than 5% of total income taxes paid (net of refunds received). The amendments in ASU 2023-09 are effective for annual periods beginning after December 15, 2024, and should be applied prospectively. The adoption of ASU 2023-09 is not expected to have a material impact on the Company’s consolidated financial statements and related disclosures.