Subsidiary Guarantors (Condensed Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
ASSETS
Cash and cash equivalents	$ 13,595	$ 14,184	$ 9,421	$ 42,389
Accounts receivable—net	115,753	130,777
Contract revenues in excess of billings	75,843	81,195
Inventories	35,734	35,963
Prepaid expenses and other current assets	78,341	67,614
Total current assets	319,266	329,733
PROPERTY AND EQUIPMENT—Net	436,691	430,210
GOODWILL AND OTHER INTANGIBLE ASSETS—Net	85,314	86,004
INVENTORIES—Noncurrent	48,706	41,646
INVESTMENTS IN JOINT VENTURES	5,791	3,761
OTHER	8,366	6,770
TOTAL	904,134	898,124
LIABILITIES AND EQUITY
Accounts payable	109,255	118,846
Accrued expenses	57,365	72,277
Revolving Credit Facility	60,000
Billings in excess of contract revenues	9,677	7,061
Current portion of long term debt	11,745	7,506
Total current liabilities	248,042	205,690
7 3/8% SENIOR NOTES	272,748	271,998
REVOLVING CREDIT FACILITY		20,000
NOTES PAYABLE	45,012	53,792
DEFERRED INCOME TAXES	73,753	74,006
OTHER	10,002	20,465
Total liabilities	649,557	645,951
TOTAL EQUITY	254,577	252,173	252,083	255,963
TOTAL	904,134	898,124
Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	13,064	12,035	8,814	41,724
Accounts receivable—net	115,335	129,978
Contract revenues in excess of billings	73,765	79,477
Inventories	35,734	35,963
Prepaid expenses and other current assets	77,988	66,919
Total current assets	315,886	324,372
PROPERTY AND EQUIPMENT—Net	436,684	430,192
GOODWILL AND OTHER INTANGIBLE ASSETS—Net	85,314	86,004
INVENTORIES—Noncurrent	48,706	41,646
INVESTMENTS IN JOINT VENTURES	5,791	3,761
RECEIVABLES FROM AFFILIATES	10,982	18,326
INVESTMENTS IN SUBSIDIARIES	3,551	3,706
OTHER	7,558	6,702
TOTAL	914,472	914,709
LIABILITIES AND EQUITY
Accounts payable	108,883	118,619
Accrued expenses	52,424	62,861
Billings in excess of contract revenues	9,557	6,964
Current portion of long term debt	1,449	1,424
Total current liabilities	172,313	189,868
NOTES PAYABLE	220	323
Deferred Tax Assets	(794)	(783)
PAYABLES TO AFFILIATES	91,359	85,859
OTHER	9,838	20,326
Total liabilities	272,936	295,593
TOTAL EQUITY	641,536	619,116
TOTAL	914,472	914,709
Non Guarantor Subsidiaries [Member]
ASSETS
Cash and cash equivalents	529	2,147	605	663
Accounts receivable—net	418	799
Contract revenues in excess of billings	2,078	1,718
Prepaid expenses and other current assets	185	218
Total current assets	3,210	4,882
PROPERTY AND EQUIPMENT—Net	7	18
RECEIVABLES FROM AFFILIATES	6,637	6,009
OTHER	1	3
TOTAL	9,855	10,912
LIABILITIES AND EQUITY
Accounts payable	372	227
Accrued expenses	764	509
Billings in excess of contract revenues	120	97
Total current liabilities	1,256	833
PAYABLES TO AFFILIATES	5,926	3,505
Total liabilities	7,182	4,338
TOTAL EQUITY	2,673	6,574
TOTAL	9,855	10,912
GLDD Corporation [Member]
ASSETS
Cash and cash equivalents	2	2	$ 2	$ 2
Prepaid expenses and other current assets	168	477
Total current assets	170	479
RECEIVABLES FROM AFFILIATES	85,327	70,738
INVESTMENTS IN SUBSIDIARIES	640,658	621,984
OTHER	807	65
TOTAL	726,962	693,266
LIABILITIES AND EQUITY
Accrued expenses	4,177	8,907
Revolving Credit Facility	60,000
Current portion of long term debt	10,296	6,082
Total current liabilities	74,473	14,989
7 3/8% SENIOR NOTES	272,748	271,998
REVOLVING CREDIT FACILITY		20,000
NOTES PAYABLE	44,792	53,469
DEFERRED INCOME TAXES	74,547	74,789
PAYABLES TO AFFILIATES	5,661	5,709
OTHER	164	139
Total liabilities	472,385	441,093
TOTAL EQUITY	254,577	252,173
TOTAL	726,962	693,266
Consolidation Eliminations [Member]
ASSETS
RECEIVABLES FROM AFFILIATES	(102,946)	(95,073)
INVESTMENTS IN SUBSIDIARIES	(644,209)	(625,690)
TOTAL	(747,155)	(720,763)
LIABILITIES AND EQUITY
PAYABLES TO AFFILIATES	(102,946)	(95,073)
Total liabilities	(102,946)	(95,073)
TOTAL EQUITY	(644,209)	(625,690)
TOTAL	$ (747,155)	$ (720,763)