Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 28, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Trading Symbol	GLDD
Entity Registrant Name	Great Lakes Dredge & Dock Corporation
Entity Central Index Key	0001372020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Address, Address Line One	2122 York Road
Entity Address, City or Town	Oak Brook
Entity Address, State or Province	IL
Entity Common Stock, Shares Outstanding		64,795,114
Entity Current Reporting Status	Yes
Entity File Number	001-33225
Entity Tax Identification Number	20-5336063
City Area Code	630
Local Phone Number	574-3000
Entity Address, Postal Zip Code	60523
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock (Par Value $0.0001)
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false