Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Costs and Expenses [Abstract]
Total costs and expenses	$ 205,323	$ 125,475	$ 382,504	$ 258,189
Gain (Loss) on Sale of Assets and Asset Impairment Charges	$ 506	5,897	$ 7,551	5,709
Net Income (Loss)		(28,629)		(34,077)
Offshore Marine Services [Member]
Operating Revenues		27,987		62,291
Costs and Expenses [Abstract]
Operating		32,509		65,888
Administrative and general		17,856		29,682
Depreciation and amortization		9,678		22,181
Total costs and expenses		60,043		117,751
Gain (Loss) on Sale of Assets and Asset Impairment Charges		(600)		4,219
Operating Income (Loss)		(32,656)		(51,241)
Other Income (Expense), Net		(5,346)		1,780
Income Tax Expense (Benefit)		(9,509)		(12,931)
Equity in Earnings (Losses) of 50% or Less Owned Companies		1,225		1,663
Net Income (Loss)		(27,268)		(34,867)
Net Income (Loss) Attributable to Noncontrolling Interests		(1,688)		(1,892)
Illinois Corn Processing LLC [Member]
Operating Revenues		39,676		78,061
Costs and Expenses [Abstract]
Operating		40,205		76,306
Administrative and general		1,363		2,109
Depreciation and amortization		1,179		2,354
Total costs and expenses		42,747		80,769
Operating Income (Loss)		(3,071)		(2,708)
Other Income (Expense), Net		487		2,335
Income Tax Expense (Benefit)		(668)		67
Net Income (Loss)		(1,916)		(440)
Net Income (Loss) Attributable to Noncontrolling Interests		(915)		(539)
Intersegment Eliminations [Member]
Operating Revenues		(520)		(1,176)
Costs and Expenses [Abstract]
Operating		(561)		(1,289)
Administrative and general		(19)		(42)
Total costs and expenses		(580)		(1,331)
Operating Income (Loss)		60		155
Other Income (Expense), Net		795		1,738
Income Tax Expense (Benefit)		300		663
Net Income (Loss)		$ 555		$ 1,230