Nature Of Operations And Accounting Policies (Schedule Of Property And Equipment By Major Classes) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 2,199,183	$ 2,238,383
Accumulated Depreciation	(866,330)	(763,803)
Property, Plant and Equipment, Net In Service	1,332,853	1,474,580
Net property and equipment	1,476,335	1,584,876	1,440,657
Offshore Support Vessels [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,047,119	1,074,170
Accumulated Depreciation	(438,528)	(398,050)
Net property and equipment	608,591	676,120
Wind Farm Utility Vessel [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	65,094	58,484
Accumulated Depreciation	(14,121)	(6,887)
Net property and equipment	50,973	51,597
Inland River Dry Cargo And Deck Barges [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	241,210	239,896
Accumulated Depreciation	(80,772)	(70,407)
Net property and equipment	160,438	169,489
Inland River Liquid Tank Barges [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	85,639	106,541
Accumulated Depreciation	(18,138)	(18,605)
Net property and equipment	67,501	87,936
Inland River Towboats [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	61,407	53,895
Accumulated Depreciation	(22,454)	(20,054)
Net property and equipment	38,953	33,841
U.S.-flag Product Tankers [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	318,497	317,894
Accumulated Depreciation	(173,278)	(154,288)
Net property and equipment	145,219	163,606
R O R O Vessels [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	18,328	15,674
Accumulated Depreciation	(3,995)	(2,492)
Net property and equipment	14,333	13,182
Harbor Tugs [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	101,762	114,974
Accumulated Depreciation	(34,017)	(32,965)
Net property and equipment	67,745	82,009
Ocean Liquid Tank Barge [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	39,238	39,073
Accumulated Depreciation	(7,335)	(5,914)
Net property and equipment	31,903	33,159
Terminal And Manufacturing Facilities [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	120,601	120,164
Accumulated Depreciation	(33,594)	(20,906)
Net property and equipment	87,007	99,258
Equipment Furniture Fixtures Vehicles And Other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	100,288	97,618
Accumulated Depreciation	(40,098)	(33,235)
Net property and equipment	$ 60,190	$ 64,383