Condensed Consolidated Statements Of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Condensed Consolidated Statements Of Operations [Abstract]
Contract revenues	$ 166,532	$ 154,959	$ 321,439	$ 310,297
Costs of contract revenues	142,643	135,193	277,528	263,089
Gross profit	23,889	19,766	43,911	47,208
General and administrative expenses	11,456	13,622	24,723	25,711
Gain on sale of assets-net	(93)	(2,513)	(124)	(2,771)
Operating income	12,526	8,657	19,312	24,268
Interest expense-net	(5,383)	(4,911)	(10,642)	(10,861)
Equity in loss of joint ventures	(8)	(123)	(24)	(714)
Loss on foreign currency transactions-net	(21)		(15)
Loss on extinguishment of debt				(5,145)
Income before income taxes	7,114	3,623	8,631	7,548
Income tax (provision) benefits	(2,768)	(1,455)	(3,332)	(2,982)
Net income	4,346	2,168	5,299	4,566
Net loss attributable to noncontrolling interests	91	(462)	206	(468)
Net income attributable to Great Lakes Dredge & Dock Corporation	$ 4,437	$ 1,706	$ 5,505	$ 4,098
Basic earnings per share attributable to Great Lakes Dredge & Dock Corporation	$ 0.07	$ 0.03	$ 0.09	$ 0.07
Basic weighted average shares	59,171	58,875	59,105	58,830
Diluted earnings per share attributable to Great Lakes Dredge & Dock Corporation	$ 0.07	$ 0.03	$ 0.09	$ 0.07
Diluted weighted average shares	59,534	59,184	59,493	59,228
Dividends declared per share	$ 0.02	$ 0.02	$ 0.04	$ 0.04