Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
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	$ 1,421		$ 1,340
Disposal Group Including Discontinued Operation Revenue	0	$ 4,663
Disposal Group, Including Discontinued Operation, Cost of Revenue	22	11,361
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	2,069
Disposal Group, Including Discontinued Operation, General and Administrative Expense	404	1,439
Disposal Group, Including Discontinued Operation, Other Expense		39
Disposal Group, Including Discontinued Operation, Other Income	0
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(426)	(10,245)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	0	(33,788)
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	(426)	(44,033)
Discontinued Operation, Tax Effect of Discontinued Operation	0	(2,327)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(426)	(41,706)
Disposal Group, Including Discontinued Operation, Other Assets, Current	1		14
Disposal Group, Including Discontinued Operation, Assets, Current	1,422		1,354
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	616		740
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	2,913		3,405
Disposal Group, Including Discontinued Operation, Liabilities, Current	3,529		4,145
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		1,340
Disposal Group Including Discontinued Operation Revenue	0	186
Disposal Group, Including Discontinued Operation, Cost of Revenue	0	238
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	213
Disposal Group, Including Discontinued Operation, General and Administrative Expense	0	186
Disposal Group, Including Discontinued Operation, Other Income	0	0
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	0	(451)
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0
Disposal Group, Including Discontinued Operation, Assets, Current	1,340		1,340
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	0		0
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	2,075		2,075
Disposal Group, Including Discontinued Operation, Liabilities, Current	2,075		2,075
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	81		0
Disposal Group Including Discontinued Operation Revenue	0	4,477
Disposal Group, Including Discontinued Operation, Cost of Revenue	22	11,123
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	1,856
Disposal Group, Including Discontinued Operation, General and Administrative Expense	404	1,253
Disposal Group, Including Discontinued Operation, Other Expense		39
Disposal Group, Including Discontinued Operation, Other Income	0
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(426)	$ (9,794)
Disposal Group, Including Discontinued Operation, Other Assets, Current	1		14
Disposal Group, Including Discontinued Operation, Assets, Current	82		14
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	616		740
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	838		1,330
Disposal Group, Including Discontinued Operation, Liabilities, Current	$ 1,454		$ 2,070