| Cover | Jul. 29, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Entity Registrant Name | Great Lakes Dredge & Dock Corporation |
| Entity Central Index Key | 0001372020 |
| Document Period End Date | Jul. 29, 2021 |
| Entity File Number | 001-33225 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 20-5336063 |
| Entity Address, Address Line One | 9811 Katy Freeway, Suite 1200 |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77024 |
| City Area Code | 364 |
| Local Phone Number | 359-1010 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock (Par Value $0.0001) |
| Trading Symbol | GLDD |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
