Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Aug. 31, 2019	Dec. 31, 2018	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	$ 4,674
Disposal Group, Including Discontinued Operation, Cost of Revenue	(273)	125	(251)	11,152
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	52	0	52	2,085
Disposal Group, Including Discontinued Operation, General and Administrative Expense	1,734	192	2,483	1,916
Disposal Group, Including Discontinued Operation, Other Income		(1,113)		(1,035)
Disposal Group, Including Discontinued Operation, Other Expense	117		117
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(1,630)	796	(2,401)	(9,444)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	(7,500)	0	(7,500)	(33,813)
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	(9,130)	796	(9,901)	(43,257)
Discontinued Operation, Tax Effect of Discontinued Operation	0	0	0	(2,326)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(9,130)	796	(9,901)	(40,931)
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	16		16			$ 1,340
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0			14
Disposal Group, Including Discontinued Operation, Assets, Current	16		16			1,354
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	901		901			740
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	1,006		1,006			3,405
Disposal Group, Including Discontinued Operation, Liabilities, Current	1,907		1,907			4,145
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	187
Disposal Group, Including Discontinued Operation, Cost of Revenue	0	0	0	139
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	0	0	212
Disposal Group, Including Discontinued Operation, General and Administrative Expense	0	0	0	187
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	(351)
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	0		0			1,340
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0			0
Disposal Group, Including Discontinued Operation, Assets, Current	0		0			1,340
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	0		0			0
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	121		121			2,075
Disposal Group, Including Discontinued Operation, Liabilities, Current	121		121			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 Revenue	0	0	0	4,487
Disposal Group, Including Discontinued Operation, Cost of Revenue	(273)	125	(251)	11,013
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	52	0	52	1,873
Disposal Group, Including Discontinued Operation, General and Administrative Expense	1,734	192	2,483	1,729
Disposal Group, Including Discontinued Operation, Other Income		(1,113)		(1,035)
Disposal Group, Including Discontinued Operation, Other Expense	117		117
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(1,630)	$ 796	(2,401)	$ (9,093)
Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net	16		16			0
Disposal Group, Including Discontinued Operation, Other Assets, Current	0		0			14
Disposal Group, Including Discontinued Operation, Assets, Current	16		16			14
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	901		901			740
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	885		885			1,330
Disposal Group, Including Discontinued Operation, Liabilities, Current	$ 1,786		$ 1,786			$ 2,070
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