| Cover | Jul. 31, 2020 |
| 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. 31, 2020 |
| Entity Emerging Growth Company | false |
| Entity File Number | 001-33225 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 20-5336063 |
| Entity Address, Address Line One | 2122 York Road |
| Entity Address, City or Town | Oak Brook |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60523 |
| City Area Code | 630 |
| Local Phone Number | 574-3000 |
| 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 |
