Segment Information (Operating Results, Capital Expenditures And Assets By Reportable Segments) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating Revenues	$ 213,928,000	$ 260,644,000
Costs and Expenses [Abstract]
Administrative and general	35,704,000	38,887,000
Depreciation and amortization	30,989,000	31,430,000
Total costs and expenses	224,161,000	269,465,000
Gains (Losses) on Asset Dispositions and Impairments, Net	217,000	(4,846,000)
Operating Income (Loss)	(10,016,000)	(13,667,000)
Other Income and Expenses [Abstract]
Derivative gains (losses), net	2,620,000	(2,996,000)
Foreign currency gains (losses), net	37,000	(1,993,000)
Other Nonoperating Income (Expense)	268,000	(44,000)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	(49,000)	3,899,000
Loss Before Taxes and Equity Earnings	(35,306,000)	(33,754,000)
Capital Expenditures	47,436,000	47,430,000
Property, Plant and Equipment, Gross	2,015,205,000		$ 2,123,201,000
Accumulated depreciation	(986,048,000)		(994,181,000)
Construction in progress	484,472,000		454,605,000
Held for sale equipment	86,332,000		0
Net property and equipment	1,599,961,000		1,583,625,000
Inventories	18,431,000		24,768,000
Goodwill	52,376,000		52,340,000
Intangible Assets, Net	25,750,000		26,392,000
Total assets	3,111,887,000	3,169,951,000	$ 3,185,419,000
Offshore Marine Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	59,853,000	93,421,000
Inland River Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	39,028,000	55,836,000
Shipping Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	57,055,000	51,407,000
Illinois Corn Processing LLC [Member]
Segment Reporting Information [Line Items]
Operating Revenues	49,609,000	39,598,000
Other Income and Expenses [Abstract]
Sales Revenue, Goods, Net	46,600,000	37,200,000
Cost of Goods Sold	43,300,000	30,700,000
Inventory, Raw Materials	2,500,000	1,600,000
Inventory, Work in Process	1,500,000	1,700,000
Other Segments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	8,383,000	20,382,000
Corporate And Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	213,928,000	260,644,000
Costs and Expenses [Abstract]
Operating Expenses	157,468,000	199,148,000
Administrative and general	35,704,000	38,887,000
Depreciation and amortization	30,989,000	31,430,000
Total costs and expenses	224,161,000	269,465,000
Gains (Losses) on Asset Dispositions and Impairments, Net	217,000	(4,846,000)
Operating Income (Loss)	(10,016,000)	(13,667,000)
Other Income and Expenses [Abstract]
Derivative gains (losses), net	2,620,000	(2,996,000)
Foreign currency gains (losses), net	37,000	(1,993,000)
Other Nonoperating Income (Expense)	268,000	(44,000)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	(49,000)	3,899,000
Capital Expenditures	47,436,000	47,430,000
Property, Plant and Equipment, Gross	2,015,205,000	2,083,035,000
Accumulated depreciation	(986,048,000)	(918,769,000)
Property, Plant and Equipment, Net In Service	1,029,157,000	1,164,266,000
Construction in progress	484,472,000	339,390,000
Held for sale equipment	86,332,000
Net property and equipment	1,599,961,000	1,503,656,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	334,370,000	483,748,000
Inventories	18,431,000	23,156,000
Goodwill	52,376,000	62,688,000
Intangible Assets, Net	25,750,000	31,955,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	218,282,000	272,310,000
Operating Segments [Member] | Offshore Marine Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	59,879,000	93,456,000
Costs and Expenses [Abstract]
Operating Expenses	48,850,000	74,355,000
Administrative and general	12,398,000	13,559,000
Depreciation and amortization	14,838,000	15,366,000
Total costs and expenses	76,086,000	103,280,000
Gains (Losses) on Asset Dispositions and Impairments, Net	(380,000)	(6,649,000)
Operating Income (Loss)	(16,587,000)	(16,473,000)
Other Income and Expenses [Abstract]
Derivative gains (losses), net	2,898,000	(9,000)
Foreign currency gains (losses), net	(1,560,000)	(17,000)
Other Nonoperating Income (Expense)	265,000	(146,000)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	2,161,000	2,975,000
Segment Profit (Loss)	(12,823,000)	(13,670,000)
Capital Expenditures	20,907,000	24,128,000
Property, Plant and Equipment, Gross	1,099,063,000	1,062,061,000
Accumulated depreciation	(557,968,000)	(504,926,000)
Property, Plant and Equipment, Net In Service	541,095,000	557,135,000
Construction in progress	117,809,000	92,873,000
Held for sale equipment	0
Net property and equipment	658,904,000	650,008,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	135,406,000	118,253,000
Inventories	3,199,000	5,360,000
Goodwill	0	13,367,000
Intangible Assets, Net	1,017,000	1,515,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	93,050,000	98,766,000
Total assets	891,576,000	887,269,000
Operating Segments [Member] | Inland River Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	39,614,000	56,607,000
Costs and Expenses [Abstract]
Operating Expenses	30,118,000	41,513,000
Administrative and general	3,912,000	3,884,000
Depreciation and amortization	7,137,000	6,889,000
Total costs and expenses	41,167,000	52,286,000
Gains (Losses) on Asset Dispositions and Impairments, Net	605,000	1,803,000
Operating Income (Loss)	(948,000)	6,124,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0	82,000
Foreign currency gains (losses), net	1,437,000	(1,121,000)
Other Nonoperating Income (Expense)	0	0
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	(2,778,000)	(274,000)
Segment Profit (Loss)	(2,289,000)	4,811,000
Capital Expenditures	1,970,000	3,916,000
Property, Plant and Equipment, Gross	379,310,000	485,881,000
Accumulated depreciation	(148,779,000)	(162,581,000)
Property, Plant and Equipment, Net In Service	230,531,000	323,300,000
Construction in progress	9,136,000	25,605,000
Held for sale equipment	86,332,000
Net property and equipment	325,999,000	348,905,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	79,478,000	101,344,000
Inventories	1,268,000	2,171,000
Goodwill	2,400,000	2,502,000
Intangible Assets, Net	5,744,000	6,692,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	45,383,000	63,768,000
Total assets	460,272,000	525,382,000
Operating Segments [Member] | Shipping Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	57,055,000	51,407,000
Costs and Expenses [Abstract]
Operating Expenses	27,234,000	37,131,000
Administrative and general	6,918,000	6,289,000
Depreciation and amortization	6,562,000	6,735,000
Total costs and expenses	40,714,000	50,155,000
Gains (Losses) on Asset Dispositions and Impairments, Net	(6,000)	0
Operating Income (Loss)	16,335,000	1,252,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0	0
Foreign currency gains (losses), net	(3,000)	(12,000)
Other Nonoperating Income (Expense)	1,000	29,000
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	26,000	1,141,000
Segment Profit (Loss)	16,359,000	2,410,000
Capital Expenditures	23,894,000	18,180,000
Property, Plant and Equipment, Gross	451,347,000	454,039,000
Accumulated depreciation	(240,652,000)	(219,662,000)
Property, Plant and Equipment, Net In Service	210,695,000	234,377,000
Construction in progress	357,296,000	218,729,000
Held for sale equipment	0
Net property and equipment	567,991,000	453,106,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	63,365,000	221,658,000
Inventories	544,000	977,000
Goodwill	1,852,000	1,852,000
Intangible Assets, Net	0	146,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	26,319,000	24,866,000
Total assets	660,071,000	702,605,000
Operating Segments [Member] | Illinois Corn Processing LLC [Member]
Segment Reporting Information [Line Items]
Operating Revenues	49,609,000	39,598,000
Costs and Expenses [Abstract]
Operating Expenses	46,289,000	33,118,000
Administrative and general	656,000	562,000
Depreciation and amortization	1,053,000	980,000
Total costs and expenses	47,998,000	34,660,000
Gains (Losses) on Asset Dispositions and Impairments, Net	0	0
Operating Income (Loss)	1,611,000	4,938,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	(187,000)	(828,000)
Foreign currency gains (losses), net	0	0
Other Nonoperating Income (Expense)	0	0
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	0	0
Segment Profit (Loss)	1,424,000	4,110,000
Capital Expenditures	686,000	776,000
Property, Plant and Equipment, Gross	51,341,000	47,256,000
Accumulated depreciation	(20,443,000)	(16,468,000)
Property, Plant and Equipment, Net In Service	30,898,000	30,788,000
Construction in progress	2,031,000	1,494,000
Held for sale equipment	0
Net property and equipment	32,929,000	32,282,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	0	0
Inventories	13,325,000	13,711,000
Goodwill	0	0
Intangible Assets, Net	0	0
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	7,969,000	11,421,000
Total assets	54,223,000	57,414,000
Operating Segments [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	8,419,000	20,452,000
Costs and Expenses [Abstract]
Operating Expenses	5,805,000	13,830,000
Administrative and general	4,223,000	7,136,000
Depreciation and amortization	455,000	500,000
Total costs and expenses	10,483,000	21,466,000
Gains (Losses) on Asset Dispositions and Impairments, Net	(2,000)	0
Operating Income (Loss)	(2,066,000)	(1,014,000)
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0	(776,000)
Foreign currency gains (losses), net	(27,000)	(40,000)
Other Nonoperating Income (Expense)	0	8,000
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	542,000	57,000
Segment Profit (Loss)	(1,551,000)	(1,765,000)
Capital Expenditures	0	3,000
Property, Plant and Equipment, Gross	3,053,000	3,521,000
Accumulated depreciation	(2,613,000)	(3,236,000)
Property, Plant and Equipment, Net In Service	440,000	285,000
Construction in progress	0	234,000
Held for sale equipment	0
Net property and equipment	440,000	519,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	56,121,000	42,493,000
Inventories	95,000	937,000
Goodwill	48,124,000	44,967,000
Intangible Assets, Net	18,989,000	23,602,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	33,524,000	71,436,000
Total assets	157,293,000	183,954,000
Operating Segments [Member] | Corporate And Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(648,000)	(876,000)
Costs and Expenses [Abstract]
Operating Expenses	(828,000)	(799,000)
Administrative and general	7,597,000	7,457,000
Depreciation and amortization	944,000	960,000
Total costs and expenses	7,713,000	7,618,000
Gains (Losses) on Asset Dispositions and Impairments, Net	0	0
Operating Income (Loss)	(8,361,000)	(8,494,000)
Other Income and Expenses [Abstract]
Derivative gains (losses), net	(91,000)	(1,465,000)
Foreign currency gains (losses), net	190,000	(803,000)
Other Nonoperating Income (Expense)	2,000	65,000
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	0	0
Capital Expenditures	(21,000)	427,000
Property, Plant and Equipment, Gross	31,091,000	30,277,000
Accumulated depreciation	(15,593,000)	(11,896,000)
Property, Plant and Equipment, Net In Service	15,498,000	18,381,000
Construction in progress	(1,800,000)	455,000
Held for sale equipment	0
Net property and equipment	13,698,000	18,836,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	0	0
Inventories	0	0
Goodwill	0	0
Intangible Assets, Net	0	0
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	12,037,000	2,053,000
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Intersegment Eliminations [Member] | Offshore Marine Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(26,000)	35,000
Intersegment Eliminations [Member] | Inland River Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(586,000)	771,000
Intersegment Eliminations [Member] | Shipping Services [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Intersegment Eliminations [Member] | Illinois Corn Processing LLC [Member]
Segment Reporting Information [Line Items]
Operating Revenues	0	0
Intersegment Eliminations [Member] | Other Segments [Member]
Segment Reporting Information [Line Items]
Operating Revenues	(36,000)	70,000
Intersegment Eliminations [Member] | Corporate And Eliminations [Member]
Segment Reporting Information [Line Items]
Operating Revenues	648,000	(876,000)
Segment Reconciling Items [Member]
Other Income and Expenses [Abstract]
Other Income (Expense) not included in Segment Profit (Loss)	28,215,000	15,054,000
Less Equity Earnings included in Segment Profit (Loss)	49,000	(3,899,000)
Cash And Near Cash Assets	$ 862,717,000	$ 792,438,000