Discontinued Operations Discontinued Operations Tables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	$ 1,340	$ 28,927
Disposal Group, Including Discontinued Operation, Revenue	4,674	97,279	$ 77,373
Disposal Group, Including Discontinued Operation, Cost of Revenue	11,290	93,738	73,268
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	2,085	12,106	13,526
Disposal Group, Including Discontinued Operation, General and Administrative Expense	2,104	6,488	7,538
Disposal Group, Including Discontinued Operation, Other Income	(1,036)		(3,089)
Disposal Group, Including Discontinued Operation, Other Income		1,888
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(9,769)	(16,941)	(13,870)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	(34,072)	0	0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	(43,841)	(16,941)	(13,870)
Provision (benefit) for deferred income taxes	(2,326)	448	147
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(41,515)	(17,389)	(14,017)
Disposal Group, Including Discontinued Operation, Inventory	0	4,616
Disposal Group, Including Discontinued Operation, Other Assets, Current	14	1,336
Disposal Group, Including Discontinued Operation, Assets, Current	1,354	34,879
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	0	85,873
Disposal Group, Including Discontinued Operation, Assets, Other Assets	0	382
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	0	86,255
Disposal Group, Including Discontinued Operation, Assets	1,354	121,134
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	740	14,029
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	3,405	11,182
Disposal Group, Including Discontinued Operation, Liabilities, Current Decommissioning and Asset Retirement Obligations	0	477
Disposal Group, Including Discontinued Operation, Liabilities, Current	4,145	25,688
Disposal Group, Including Discontinued Operation, Liabilities, Decommissioning and Asset Retirement Obligations	0	46,185
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent	0	2,040
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	0	48,225
Disposal Group, Including Discontinued Operation, Liabilities	4,145	73,913
Offshore Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	0	27,385
Disposal Group, Including Discontinued Operation, Revenue	4,487	96,741	76,622
Disposal Group, Including Discontinued Operation, Cost of Revenue	11,151	92,674	70,032
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	1,873	10,678	12,164
Disposal Group, Including Discontinued Operation, General and Administrative Expense	1,917	5,705	6,451
Disposal Group, Including Discontinued Operation, Other Income	(1,036)
Disposal Group, Including Discontinued Operation, Other Income		2,453	3
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(9,418)	(14,769)	(12,028)
Disposal Group, Including Discontinued Operation, Inventory	0	4,616
Disposal Group, Including Discontinued Operation, Other Assets, Current	14	1,292
Disposal Group, Including Discontinued Operation, Assets, Current	14	33,293
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	0	85,873
Disposal Group, Including Discontinued Operation, Assets, Other Assets	0	382
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	0	86,255
Disposal Group, Including Discontinued Operation, Assets	14	119,548
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	740	13,942
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	1,330	8,904
Disposal Group, Including Discontinued Operation, Liabilities, Current Decommissioning and Asset Retirement Obligations	0	0
Disposal Group, Including Discontinued Operation, Liabilities, Current	2,070	22,846
Disposal Group, Including Discontinued Operation, Liabilities, Decommissioning and Asset Retirement Obligations	0	0
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent	0	2,040
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	0	2,040
Disposal Group, Including Discontinued Operation, Liabilities	2,070	24,886
Maritech [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	1,340	1,542
Disposal Group, Including Discontinued Operation, Revenue	187	538	751
Disposal Group, Including Discontinued Operation, Cost of Revenue	139	1,064	3,236
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	212	1,428	1,362
Disposal Group, Including Discontinued Operation, General and Administrative Expense	187	783	1,087
Disposal Group, Including Discontinued Operation, Other Income	0	(565)	(3,092)
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(351)	(2,172)	$ (1,842)
Disposal Group, Including Discontinued Operation, Inventory	0	0
Disposal Group, Including Discontinued Operation, Other Assets, Current	0	44
Disposal Group, Including Discontinued Operation, Assets, Current	1,340	1,586
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	0	0
Disposal Group, Including Discontinued Operation, Assets, Other Assets	0	0
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	0	0
Disposal Group, Including Discontinued Operation, Assets	1,340	1,586
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	0	87
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	2,075	2,278
Disposal Group, Including Discontinued Operation, Liabilities, Current Decommissioning and Asset Retirement Obligations	0	477
Disposal Group, Including Discontinued Operation, Liabilities, Current	2,075	2,842
Disposal Group, Including Discontinued Operation, Liabilities, Decommissioning and Asset Retirement Obligations	0	46,185
Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent	0	0
Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent	0	46,185
Disposal Group, Including Discontinued Operation, Liabilities	$ 2,075	$ 49,027