Segment Information (Operating Results, Capital Expenditures And Assets By Reportable Segments) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Segment Reporting Information [Line Items]
Total assets	$ 3,845,817,000		$ 3,705,762,000		$ 3,845,817,000		$ 3,705,762,000		$ 3,928,134,000
Operating Revenue:
External customers	494,422,000		509,283,000		992,307,000		947,294,000
Intersegment	0		0		0		0
Operating Revenues	494,422,000		509,283,000		992,307,000		947,294,000
Costs and Expenses [Abstract]
Operating Expenses	403,210,000		409,365,000		787,322,000		751,108,000
Administrative and general	45,120,000		39,170,000		91,298,000		80,824,000
Depreciation and amortization	43,685,000		39,330,000		83,012,000		77,660,000
Total costs and expenses	492,015,000		487,865,000		961,632,000		909,592,000
Gains on Asset Dispositions and Impairments Net	4,419,000		10,301,000		9,961,000		17,556,000
Operating Income	6,826,000		31,719,000		40,636,000		55,258,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	3,487,000		(6,601,000)		(632,000)		(9,919,000)
Foreign currency gains (losses), net	(992,000)		1,416,000		1,560,000		6,475,000
Other Nonoperating Income (Expense)	443,000		(56,000)		389,000		(234,000)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	1,051,000		872,000		2,293,000		914,000
Other Income (Expense) not included in Segment Profit	6,824,000		(11,922,000)		974,000		(16,744,000)
Less Equity Earnings included in Segment Profit	1,051,000		872,000		2,293,000		914,000
Income from Continuing Operations Before Income Tax Expense and Equity in Earnings of 50% or Less Owned Companies	16,588,000		14,556,000		42,927,000		34,836,000
Capital Expenditures					186,541,000		127,407,000
Property and Equipment	2,370,432,000		2,007,125,000		2,370,432,000		2,007,125,000		2,150,231,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	323,874,000		208,021,000		323,874,000		208,021,000		249,753,000
Inventories	72,929,000	[1]	83,120,000		72,929,000	[1]	83,120,000		69,109,000
Goodwill	57,054,000		54,454,000		57,054,000		54,454,000		57,054,000
Intangible Assets, Net	21,116,000		17,396,000		21,116,000		17,396,000		21,528,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	452,247,000	[2]	438,339,000	[2]	452,247,000	[2]	438,339,000	[2]
Cash And Near Cash Assets	544,614,000	[2]	796,088,000	[2]	544,614,000	[2]	796,088,000	[2]
Assets of Disposal Group, Including Discontinued Operation	3,551,000		101,219,000		3,551,000		101,219,000
Offshore Marine Services [Member]
Operating Revenue:
External customers	123,359,000		93,360,000		244,297,000		173,683,000
Intersegment	(83,000)		26,000		65,000		47,000
Operating Revenues	123,276,000		93,386,000		244,362,000		173,730,000
Costs and Expenses [Abstract]
Operating Expenses	94,084,000		68,242,000		169,424,000		131,262,000
Administrative and general	13,146,000		11,078,000		25,002,000		22,848,000
Depreciation and amortization	15,859,000		12,205,000		28,741,000		24,738,000
Total costs and expenses	123,089,000		91,525,000		223,167,000		178,848,000
Gains on Asset Dispositions and Impairments Net	624,000		3,607,000		2,469,000		7,971,000
Operating Income	811,000		5,468,000		23,664,000		2,853,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0		0		0		0
Foreign currency gains (losses), net	(354,000)		(408,000)		769,000		317,000
Other Nonoperating Income (Expense)	11,000		0		11,000		0
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	1,001,000		200,000		2,830,000		935,000
Segment Profit (Loss)	1,469,000		5,260,000		27,274,000		4,105,000
Capital Expenditures					64,383,000		33,025,000
Property and Equipment	789,831,000		620,146,000		789,831,000		620,146,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	68,081,000		57,697,000		68,081,000		57,697,000
Inventories	5,738,000	[1]	4,164,000		5,738,000	[1]	4,164,000
Goodwill	13,367,000		13,367,000		13,367,000		13,367,000
Intangible Assets, Net	5,029,000		6,992,000		5,029,000		6,992,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	148,525,000	[2]	130,342,000	[2]	148,525,000	[2]	130,342,000	[2]
Total segment assets	1,030,571,000		832,708,000		1,030,571,000		832,708,000
Aviation Services [Member]
Operating Revenue:
External customers	62,983,000		68,475,000		124,035,000		124,630,000
Intersegment	2,000		18,000		2,000		18,000
Operating Revenues	62,985,000		68,493,000		124,037,000		124,648,000
Costs and Expenses [Abstract]
Operating Expenses	39,002,000		42,457,000		78,678,000		75,922,000
Administrative and general	7,195,000		6,229,000		16,872,000		13,249,000
Depreciation and amortization	10,464,000		12,390,000		20,094,000		24,309,000
Total costs and expenses	56,661,000		61,076,000		115,644,000		113,480,000
Gains on Asset Dispositions and Impairments Net	1,077,000		6,172,000		2,842,000		8,366,000
Operating Income	7,401,000		13,589,000		11,235,000		19,534,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	(180,000)		(811,000)		(304,000)		(501,000)
Foreign currency gains (losses), net	(12,000)		338,000		905,000		691,000
Other Nonoperating Income (Expense)	0		0		30,000		0
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	756,000		1,054,000		(5,663,000)		955,000
Segment Profit (Loss)	7,965,000		14,170,000		6,203,000		20,679,000
Capital Expenditures					87,034,000		50,233,000
Property and Equipment	773,884,000		629,619,000		773,884,000		629,619,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	41,882,000		35,341,000		41,882,000		35,341,000
Inventories	26,496,000	[1]	24,788,000		26,496,000	[1]	24,788,000
Goodwill	352,000		352,000		352,000		352,000
Intangible Assets, Net	0		0		0		0
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	79,699,000	[2]	63,643,000	[2]	79,699,000	[2]	63,643,000	[2]
Total segment assets	922,313,000		753,743,000		922,313,000		753,743,000
Inland River Services [Member]
Operating Revenue:
External customers	49,750,000		38,682,000		99,646,000		82,610,000
Intersegment	3,552,000		2,760,000		7,146,000		5,301,000
Operating Revenues	53,302,000		41,442,000		106,792,000		87,911,000
Costs and Expenses [Abstract]
Operating Expenses	37,463,000		28,717,000		72,646,000		56,601,000
Administrative and general	3,773,000		3,166,000		7,755,000		5,863,000
Depreciation and amortization	7,244,000		5,791,000		14,251,000		11,413,000
Total costs and expenses	48,480,000		37,674,000		94,652,000		73,877,000
Gains on Asset Dispositions and Impairments Net	858,000		(22,000)		2,785,000		675,000
Operating Income	5,680,000		3,746,000		14,925,000		14,709,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0		0		0		0
Foreign currency gains (losses), net	(71,000)		0		(93,000)		0
Other Nonoperating Income (Expense)	0		3,000		0		4,000
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	439,000		666,000		689,000		410,000
Segment Profit (Loss)	6,048,000		4,415,000		15,521,000		15,123,000
Capital Expenditures					13,108,000		33,137,000
Property and Equipment	377,326,000		338,289,000		377,326,000		338,289,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	53,859,000		42,378,000		53,859,000		42,378,000
Inventories	2,038,000	[1]	2,511,000		2,038,000	[1]	2,511,000
Goodwill	4,345,000		1,743,000		4,345,000		1,743,000
Intangible Assets, Net	8,377,000		908,000		8,377,000		908,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	49,890,000	[2]	41,543,000	[2]	49,890,000	[2]	41,543,000	[2]
Total segment assets	495,835,000		427,372,000		495,835,000		427,372,000
Marine Transportation Services [Member]
Operating Revenue:
External customers	25,704,000		24,249,000		51,900,000		41,473,000
Intersegment	88,000		87,000		175,000		175,000
Operating Revenues	25,792,000		24,336,000		52,075,000		41,648,000
Costs and Expenses [Abstract]
Operating Expenses	16,722,000		13,584,000		32,480,000		22,563,000
Administrative and general	2,934,000		2,146,000		5,409,000		3,563,000
Depreciation and amortization	5,666,000		5,728,000		11,317,000		10,706,000
Total costs and expenses	25,322,000		21,458,000		49,206,000		36,832,000
Gains on Asset Dispositions and Impairments Net	0		0		0		0
Operating Income	470,000		2,878,000		2,869,000		4,816,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0		0		0		0
Foreign currency gains (losses), net	(3,000)		6,000		6,000		22,000
Other Nonoperating Income (Expense)	49,000		56,000		79,000		56,000
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	(774,000)		0		(991,000)		0
Segment Profit (Loss)	(258,000)		2,940,000		1,963,000		4,894,000
Capital Expenditures					4,084,000		8,315,000
Property and Equipment	203,995,000		249,818,000		203,995,000		249,818,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	90,626,000		0		90,626,000		0
Inventories	0	[1]	365,000		0	[1]	365,000
Goodwill	550,000		606,000		550,000		606,000
Intangible Assets, Net	1,318,000		1,732,000		1,318,000		1,732,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	3,691,000	[2]	5,308,000	[2]	3,691,000	[2]	5,308,000	[2]
Total segment assets	300,180,000		257,829,000		300,180,000		257,829,000
Emergency and Crisis Services [Member]
Operating Revenue:
External customers	8,456,000		21,275,000		18,619,000		50,108,000
Intersegment	(17,000)		0		35,000		0
Operating Revenues	8,439,000		21,275,000		18,654,000		50,108,000
Costs and Expenses [Abstract]
Operating Expenses	5,808,000		12,328,000		12,681,000		27,104,000
Administrative and general	4,211,000		3,555,000		7,465,000		6,366,000
Depreciation and amortization	491,000		498,000		975,000		1,000,000
Total costs and expenses	10,510,000		16,381,000		21,121,000		34,470,000
Gains on Asset Dispositions and Impairments Net	0		0		5,000
Operating Income	(2,071,000)		4,894,000		(2,462,000)		15,638,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0		0		0		0
Foreign currency gains (losses), net	(20,000)		(7,000)		(6,000)		(58,000)
Other Nonoperating Income (Expense)	0		2,000		0		2,000
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	147,000		0		214,000
Segment Profit (Loss)	(1,944,000)		4,889,000		(2,254,000)		15,582,000
Capital Expenditures					420,000		25,000
Property and Equipment	1,406,000		855,000		1,406,000		855,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	441,000		0		441,000		0
Inventories	752,000	[1]	404,000		752,000	[1]	404,000
Goodwill	37,138,000		37,084,000		37,138,000		37,084,000
Intangible Assets, Net	5,531,000		7,290,000		5,531,000		7,290,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	16,629,000	[2]	32,894,000	[2]	16,629,000	[2]	32,894,000	[2]
Total segment assets	61,897,000		78,527,000		61,897,000		78,527,000
Commodity Trading And Logistics [Member]
Operating Revenue:
External customers	206,745,000		245,321,000		416,441,000		439,333,000
Intersegment	0		0		0		0
Operating Revenues	206,745,000		245,321,000		416,441,000		439,333,000
Costs and Expenses [Abstract]
Operating Expenses	202,126,000		237,644,000		405,359,000		424,662,000
Administrative and general	3,411,000		2,202,000		6,552,000		4,862,000
Depreciation and amortization	1,591,000		12,000		2,651,000		25,000
Total costs and expenses	207,128,000		239,858,000		414,562,000		429,549,000
Gains on Asset Dispositions and Impairments Net	0		0		0		0
Operating Income	(383,000)		5,463,000		1,879,000		9,784,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	3,393,000		828,000		454,000		(3,922,000)
Foreign currency gains (losses), net	(14,000)		(16,000)		65,000		(21,000)
Other Nonoperating Income (Expense)	0		0		0		0
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	0		(1,051,000)		6,154,000		(1,000,000)
Segment Profit (Loss)	2,996,000		5,224,000		8,552,000		4,841,000
Capital Expenditures					0		0
Property and Equipment	41,660,000		131,000		41,660,000		131,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	0		12,929,000		0		12,929,000
Inventories	36,617,000	[1]	49,255,000		36,617,000	[1]	49,255,000
Goodwill	0		0		0		0
Intangible Assets, Net	502,000		0		502,000		0
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	62,889,000	[2]	76,119,000	[2]	62,889,000	[2]	76,119,000	[2]
Total segment assets	141,668,000		138,434,000		141,668,000		138,434,000
Inventory, Raw Materials	3,400,000				3,400,000
Inventory, Work in Process	2,400,000				2,400,000
Other [Member]
Operating Revenue:
External customers	17,425,000		17,921,000		37,369,000		35,457,000
Intersegment	130,000		0		130,000		0
Operating Revenues	17,555,000		17,921,000		37,499,000		35,457,000
Costs and Expenses [Abstract]
Operating Expenses	11,562,000		9,158,000		23,376,000		18,300,000
Administrative and general	2,996,000		3,210,000		5,813,000		5,830,000
Depreciation and amortization	1,904,000		2,237,000		4,062,000		4,526,000
Total costs and expenses	16,462,000		14,605,000		33,251,000		28,656,000
Gains on Asset Dispositions and Impairments Net	1,860,000		544,000		1,860,000		544,000
Operating Income	2,953,000		3,860,000		6,108,000		7,345,000
Other Income and Expenses [Abstract]
Derivative gains (losses), net	0		0		0		0
Foreign currency gains (losses), net	(7,000)		(24,000)		(23,000)		(23,000)
Other Nonoperating Income (Expense)	208,000		0		208,000		(1,000)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	(518,000)		3,000		(940,000)		(386,000)
Segment Profit (Loss)	2,636,000		3,839,000		5,353,000		6,935,000
Capital Expenditures					14,731,000		1,498,000
Property and Equipment	160,265,000		148,929,000		160,265,000		148,929,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	68,985,000		59,676,000		68,985,000		59,676,000
Inventories	1,288,000	[1]	1,633,000		1,288,000	[1]	1,633,000
Goodwill	1,302,000		1,302,000		1,302,000		1,302,000
Intangible Assets, Net	359,000		474,000		359,000		474,000
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	52,950,000	[2]	61,548,000	[2]	52,950,000	[2]	61,548,000	[2]
Total segment assets	285,149,000		273,562,000		285,149,000		273,562,000
Corporate And Eliminations [Member]
Operating Revenue:
External customers	0		0		0		0
Intersegment	(3,672,000)		(2,891,000)		(7,553,000)		(5,541,000)
Operating Revenues	(3,672,000)		(2,891,000)		(7,553,000)		(5,541,000)
Costs and Expenses [Abstract]
Operating Expenses	(3,557,000)		(2,765,000)		(7,322,000)		(5,306,000)
Administrative and general	7,454,000		7,584,000		16,430,000		18,243,000
Depreciation and amortization	466,000		469,000		921,000		943,000
Total costs and expenses	4,363,000		5,288,000		10,029,000		13,880,000
Gains on Asset Dispositions and Impairments Net	0		0		0		0
Operating Income	(8,035,000)		(8,179,000)		(17,582,000)		(19,421,000)
Other Income and Expenses [Abstract]
Derivative gains (losses), net	274,000		(6,618,000)		(782,000)		(5,496,000)
Foreign currency gains (losses), net	(511,000)		1,527,000		(63,000)		5,547,000
Other Nonoperating Income (Expense)	175,000		(117,000)		61,000		(295,000)
Equity in Earnings (Losses) of 50% or Less Owned Companies, Net of Tax	0		0		0		0
Capital Expenditures					2,781,000		1,174,000
Property and Equipment	22,065,000		19,338,000		22,065,000		19,338,000
Investments, at Equity, and Advances to 50% or Less Owned Companies	0		0		0		0
Inventories	0	[1]	0		0	[1]	0
Goodwill	0		0		0		0
Intangible Assets, Net	0		0		0		0
Other Current And Long-Term Assets, Excluding Cash And Near Cash Assets	$ 37,974,000	[2]	$ 26,942,000	[2]	$ 37,974,000	[2]	$ 26,942,000	[2]

[1] Inventories for Commodity Trading and Logistics includes raw materials of $3.4 million and work in process of $2.4 million resulting from the acquisition of ICP (see Note 4).

[2] Cash and near cash assets includes cash, cash equivalents, restricted cash, marketable securities, construction reserve funds and Title XI reserve funds.