Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	GLDD
Entity Registrant Name	Great Lakes Dredge & Dock CORP
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		63,826,303
Entity Current Reporting Status	Yes
Entity File Number	001-33225
Entity Tax Identification Number	205336063
City Area Code	630
Local Phone Number	574-3000
Entity Address, Postal Zip Code	60523