Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Aug. 31, 2019	Mar. 01, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group Including Discontinued Operation Revenue	$ 0	$ 0	$ 0	$ 0
Disposal Group, Including Discontinued Operation, Cost of Revenue	(274)	0	(334)	22
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	0	0	0
Disposal Group, Including Discontinued Operation, General and Administrative Expense	111	345	316	749
Disposal Group, Including Discontinued Operation, Other Income		0		0
Disposal Group, Including Discontinued Operation, Other Expense	0		0
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	163	(345)	18	(771)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	0	0	0	0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	163	(345)	18	(771)
Discontinued Operation, Tax Effect of Discontinued Operation	0	0	0	0
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	163	(345)	18	(771)
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	0		0		$ 0
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0		0
Disposal Group, Including Discontinued Operation, Assets, Current	0		0		0
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	1,231		1,231		1,233
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	642		642		865
Disposal Group, Including Discontinued Operation, Liabilities, Current	1,873		1,873		2,098
Maritech [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group Including Discontinued Operation Revenue	0	0	0	0
Disposal Group, Including Discontinued Operation, Cost of Revenue	0	0	0	0
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	0	0	0
Disposal Group, Including Discontinued Operation, General and Administrative Expense	0	0	0	0
Disposal Group, Including Discontinued Operation, Other Expense	0	0	0	0
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	0	0	0	0
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	0		0		0
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0		0
Disposal Group, Including Discontinued Operation, Assets, Current	0		0		0
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	0		0		0
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	228		228		120
Disposal Group, Including Discontinued Operation, Liabilities, Current	228		228		120
Offshore Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group Including Discontinued Operation Revenue	0	0	0	0
Disposal Group, Including Discontinued Operation, Cost of Revenue	(274)	0	(334)	22
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	0	0	0
Disposal Group, Including Discontinued Operation, General and Administrative Expense	111	345	316	749
Disposal Group, Including Discontinued Operation, Other Income		0		0
Disposal Group, Including Discontinued Operation, Other Expense	0		0
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	163	$ (345)	18	$ (771)
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	0		0		0
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0		0
Disposal Group, Including Discontinued Operation, Assets, Current	0		0		0
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	1,231		1,231		1,233
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	414		414		745
Disposal Group, Including Discontinued Operation, Liabilities, Current	$ 1,645		$ 1,645		$ 1,978
Discontinued Operations, Disposed of by Sale | Offshore Division
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Reserve, Other Receivables						$ 1,500
Disposal Group, Including Discontinued Operation, Consideration, Additional Receivable							$ 7,500