Subsidiary Guarantors (Condensed Consolidated Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 70,791	$ 113,288
Accounts receivable - net	112,897	120,268
Contract revenues in excess of billings	50,889	26,412
Inventories	48,696	33,426
Prepaid expenses and other current assets	42,932	32,384
Total current assets	326,205	325,778
Property and equipment - net	316,460	310,520
Goodwill and other intangiable assets - net	98,729	98,863
Inventories- noncurrent	23,206	30,103
Investments in joint ventures	6,899	6,923
Other	18,461	16,273
Total	789,960	788,460
LIABILITIES AND EQUITY
Accounts payable	80,652	82,745
Accrued expenses	27,477	31,121
Billings in excess of contract revenues	19,999	13,627
Current portion of long term debt	2,658	3,033
Total current liabilities	130,786	130,526
Long term note payable	2,500	2,500
7 3/8% Senior notes	250,000	250,000
Deferred income taxes	102,920	104,352
Other	8,153	8,545
Total liabilities	494,359	495,923
EQUITY:
Total Great Lakes Dredge & Dock Corporation Equity	295,373	291,969
NONCONTROLLING INTERESTS	228	568
Total equity	295,601	292,537
TOTAL	789,960	788,460
GLDD Corporation [Member]
ASSETS
Receivables from affiliates	7,685	49,724
Prepaid expenses and other current assets	6,473	16,330
Total current assets	14,158	66,054
investments in subsidiaries	645,270	627,754
Other	6,919	5,547
Total	666,347	699,355
LIABILITIES AND EQUITY
Accounts payable	334
Payables to affiliates	8,180	44,053
Accrued expenses	8,469	8,047
Total current liabilities	16,983	52,100
7 3/8% Senior notes	250,000	250,000
Deferred income taxes	102,994	103,959
Other	769	759
Total liabilities	370,746	406,818
EQUITY:
Total Great Lakes Dredge & Dock Corporation Equity	295,373	291,969
NONCONTROLLING INTERESTS	228	568
Total equity	295,601	292,537
TOTAL	666,347	699,355
Subsidiary Guarantors [Member]
ASSETS
Cash and cash equivalents	70,623	108,985
Accounts receivable - net	112,289	118,530
Receivables from affiliates	56,184	79,683
Contract revenues in excess of billings	50,932	26,323
Inventories	48,696	33,426
Prepaid expenses and other current assets	36,429	15,929
Total current assets	375,153	382,876
Property and equipment - net	316,408	310,459
Goodwill and other intangiable assets - net	98,369	98,474
Inventories- noncurrent	23,206	30,103
Investments in joint ventures	6,899	6,923
investments in subsidiaries	3,397	4,385
Other	11,539	10,729
Total	834,971	843,949
LIABILITIES AND EQUITY
Accounts payable	79,668	81,971
Payables to affiliates	60,546	85,865
Accrued expenses	18,290	22,445
Billings in excess of contract revenues	19,939	13,607
Current portion of long term debt	2,658	3,033
Total current liabilities	181,101	206,921
Long term note payable	2,500	2,500
Deferred income taxes	(74)	399
Other	7,384	7,786
Total liabilities	190,911	217,606
EQUITY:
Total Great Lakes Dredge & Dock Corporation Equity	644,060	626,343
Total equity	644,060	626,343
TOTAL	834,971	843,949
Non-Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	168	4,303
Accounts receivable - net	608	1,738
Receivables from affiliates	8,344	7,729
Contract revenues in excess of billings	191	153
Prepaid expenses and other current assets	30	125
Total current assets	9,341	14,048
Property and equipment - net	52	61
Goodwill and other intangiable assets - net	360	389
Other	3	3
Total	9,756	14,501
LIABILITIES AND EQUITY
Accounts payable	650	774
Payables to affiliates	3,659	7,234
Accrued expenses	718	629
Billings in excess of contract revenues	122	68
Total current liabilities	5,149	8,705
Total liabilities	5,149	8,705
EQUITY:
Total Great Lakes Dredge & Dock Corporation Equity	4,607	5,796
Total equity	4,607	5,796
TOTAL	9,756	14,501
Eliminations [Member]
ASSETS
Receivables from affiliates	(72,213)	(137,136)
Contract revenues in excess of billings	(234)	(64)
Total current assets	(72,447)	(137,200)
investments in subsidiaries	(648,667)	(632,139)
Other		(6)
Total	(721,114)	(769,345)
LIABILITIES AND EQUITY
Payables to affiliates	(72,385)	(137,152)
Billings in excess of contract revenues	(62)	(48)
Total current liabilities	(72,447)	(137,200)
Deferred income taxes		(6)
Total liabilities	(72,447)	(137,206)
EQUITY:
Total Great Lakes Dredge & Dock Corporation Equity	(648,667)	(632,139)
Total equity	(648,667)	(632,139)
TOTAL	$ (721,114)	$ (769,345)