Discontinued Operations Discontinued Operations Tables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	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, Accounts, Notes and Loans Receivable, Net	$ 0	$ 1,340
Disposal Group, Including Discontinued Operation, Revenue	0	4,674	$ 97,279
Disposal Group, Including Discontinued Operation, Cost of Revenue	(192)	11,290	93,738
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	52	2,085	12,106
Disposal Group, Including Discontinued Operation, General and Administrative Expense	2,618	2,104	6,488
Disposal Group, Including Discontinued Operation, Other Income		(1,036)
Disposal Group, Including Discontinued Operation, Other Income	235		1,888
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(2,713)	(9,769)	(16,941)
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax	(7,500)	(34,072)	0
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	(10,213)	(43,841)	(16,941)
Provision (benefit) for deferred income taxes	0	(2,326)	448
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(10,213)	(41,515)	(17,389)
Disposal Group, Including Discontinued Operation, Other Assets, Current	0	14
Disposal Group, Including Discontinued Operation, Assets, Current	0	1,354
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	1,233	740
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	865	3,405
Disposal Group, Including Discontinued Operation, Liabilities, Current	2,098	4,145
Offshore Division [Member] | Discontinued Operations, Disposed of by Sale [Member]
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
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	0
Disposal Group, Including Discontinued Operation, Revenue	0	4,487	96,741
Disposal Group, Including Discontinued Operation, Cost of Revenue	(192)	11,151	92,674
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	52	1,873	10,678
Disposal Group, Including Discontinued Operation, General and Administrative Expense	2,618	1,917	5,705
Disposal Group, Including Discontinued Operation, Other Income		(1,036)
Disposal Group, Including Discontinued Operation, Other Income	117		2,453
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(2,595)	(9,418)	(14,769)
Disposal Group, Including Discontinued Operation, Other Assets, Current	0	14
Disposal Group, Including Discontinued Operation, Assets, Current	0	14
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	1,233	740
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	745	1,330
Disposal Group, Including Discontinued Operation, Liabilities, Current	1,978	2,070
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	0	1,340
Disposal Group, Including Discontinued Operation, Revenue	0	187	538
Disposal Group, Including Discontinued Operation, Cost of Revenue	0	139	1,064
Disposal Group, Including Discontinued Operation, Depreciation and Amortization	0	212	1,428
Disposal Group, Including Discontinued Operation, General and Administrative Expense	0	187	783
Disposal Group, Including Discontinued Operation, Other Income		0	(565)
Disposal Group, Including Discontinued Operation, Other Income	118
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, before Income Tax	(118)	(351)	$ (2,172)
Disposal Group, Including Discontinued Operation, Other Assets, Current	0	0
Disposal Group, Including Discontinued Operation, Assets, Current	0	1,340
Disposal Group, Including Discontinued Operation, Accounts Payable, Current	0	0
Disposal Group, Including Discontinued Operation, Accrued Liabilities, Current	120	2,075
Disposal Group, Including Discontinued Operation, Liabilities, Current	$ 120	$ 2,075