Share-Based Compensation	9 Months Ended
Sep. 30, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	6. Share-based compensation On May 5, 2021, the Company’s stockholders approved the Great Lakes Dredge & Dock Corporation 2021 Long-Term Incentive Plan (the “Incentive Plan”), which previously had been approved by the Company’s board of directors subject to stockholder approval. The Incentive Plan replaces the 2017 Long-Term Incentive Plan (the “Prior Plan”) and is largely based on the Prior Plan, but with updates to the available shares and other administrative changes. The Incentive Plan permits the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 1.5 million shares of common stock, plus the number of shares that remained available for future grant under the Prior Plan as of the effectiveness of the Incentive Plan. The Prior Plan permitted the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 3.3 million shares of common stock, plus an additional 1.7 million shares underlying equity awards issued under the 2007 Long-Term Incentive Plan. During the nine months ended September 30, 2022, the Company granted 606 thousand restricted stock units to certain employees. In addition, all non-employee directors on the Company’s board of directors are paid a portion of their board-related compensation in stock grants or restricted stock units. Compensation cost charged to expense related to share-based compensation arrangements was $1,285 and $1,207 for the three months ended September 30, 2022 and 2021, respectively. Compensation cost charged to expense related to share-based compensation arrangements was $2,837 and $3,772 for the nine months ended September 30, 2022 and 2021, respectively.

Share-Based Compensation

9 Months Ended

Sep. 30, 2022

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Share-based compensation

On May 5, 2021, the Company’s stockholders approved the Great Lakes Dredge & Dock Corporation 2021 Long-Term Incentive Plan (the “Incentive Plan”), which previously had been approved by the Company’s board of directors subject to stockholder approval. The Incentive Plan replaces the 2017 Long-Term Incentive Plan (the “Prior Plan”) and is largely based on the Prior Plan, but with updates to the available shares and other administrative changes. The Incentive Plan permits the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 1.5 million shares of common stock, plus the number of shares that remained available for future grant under the Prior Plan as of the effectiveness of the Incentive Plan.

The Prior Plan permitted the granting of stock options, stock appreciation rights, restricted stock and restricted stock units to the Company’s employees and directors for up to 3.3 million shares of common stock, plus an additional 1.7 million shares underlying equity awards issued under the 2007 Long-Term Incentive Plan.

During the nine months ended September 30, 2022, the Company granted 606 thousand restricted stock units to certain employees. In addition, all non-employee directors on the Company’s board of directors are paid a portion of their board-related compensation in stock grants or restricted stock units. Compensation cost charged to expense related to share-based compensation arrangements was $1,285 and $1,207 for the three months ended September 30, 2022 and 2021, respectively. Compensation cost charged to expense related to share-based compensation arrangements was $2,837 and $3,772 for the nine months ended September 30, 2022 and 2021, respectively.