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Noncontrolling Interests in Subsidiaries (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($) equipment	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) equipment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	$ 135,376				$ 120,119				$ 135,376	$ 120,119
Net Income (Loss)	(90,289)	$ (34,026)	$ (50,933)	$ (20,524)	(49,853)	$ 16,405	$ (8,501)	$ (17,901)	(195,772)	(59,850)	$ 124,347
Net Income (Loss) Attributable to Noncontrolling Interest									20,125	8,932	24,215
Noncontrolling Interest, Increase from Subsidiary Equity Issuance										400	152,423
Purchase of subsidiary shares from noncontrolling interests										(497)	3,110
Dividends paid to noncontrolling interests									3,753	5,199	6,070
Windcat Workboats Ltd. [Member]
Noncontrolling Interest [Line Items]
Net Assets					29,900					29,900
Illinois Corn Processing Llc [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries					22,272					22,272
Net Assets					74,200					74,200
Net Income (Loss)											38,400
Net Income (Loss) Attributable to Noncontrolling Interest											10,300
Offshore Marine Services [Member] \| Windcat Workboats Ltd. [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	5,266				7,484				5,266	7,484
Net Assets	$ 21,100								21,100
Net Income (Loss)									(4,500)	1,600	1,900
Net Income (Loss) Attributable to Noncontrolling Interest									$ (1,100)	400	500
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	25.00%								25.00%
Offshore Marine Services [Member] \| Other Offshore Marine Services Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	$ 277				470				$ 277	470
Inland River Services [Member]
Noncontrolling Interest [Line Items]
Purchase of subsidiary shares from noncontrolling interests											1,000
Payments for Repurchase of Redeemable Noncontrolling Interest											3,100
Dividends paid to noncontrolling interests											2,100
Inland River Services [Member] \| Other Inland River Services Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	980				1,146				980	1,146
Shipping Services [Member] \| Sea-Vista [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	106,054				88,290				106,054	88,290
Net Assets	$ 216,400				180,200				216,400	180,200
Net Income (Loss)									36,300	5,200	25,100
Net Income (Loss) Attributable to Noncontrolling Interest									$ 17,800	2,600	$ 12,300
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	49.00%								49.00%		49.00%
Noncontrolling Interest, Increase from Subsidiary Equity Issuance											$ 145,700
Payments of Stock Issuance Costs											$ 3,200
Illinois Corn Processing Llc [Member] \| Illinois Corn Processing Llc [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	$ 22,647								$ 22,647
Net Assets		$ 75,500
Net Income (Loss)									12,300	19,500
Net Income (Loss) Attributable to Noncontrolling Interest									$ 3,700	5,900
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	30.00%								30.00%
Other Segments [Member] \| Other Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling interests in subsidiaries	$ 152				$ 457				$ 152	$ 457
U.S.-flag Product Tankers [Member]
Noncontrolling Interest [Line Items]
Unrecorded Unconditional Purchase Obligation, Maximum Quantity \| equipment	1								1
U.S.-flag Product Tankers [Member] \| Shipping Services [Member] \| Sea-Vista [Member]
Noncontrolling Interest [Line Items]
Unrecorded Unconditional Purchase Obligation, Maximum Quantity \| equipment	1								1
Minimum [Member] \| Offshore Marine Services [Member] \| Other Offshore Marine Services Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	1.80%								1.80%
Minimum [Member] \| Inland River Services [Member] \| Other Inland River Services Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	3.00%								3.00%
Minimum [Member] \| Other Segments [Member] \| Other Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	5.00%								5.00%
Maximum [Member] \| Offshore Marine Services [Member] \| Other Offshore Marine Services Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	30.00%								30.00%
Maximum [Member] \| Inland River Services [Member] \| Other Inland River Services Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	51.80%								51.80%
Maximum [Member] \| Other Segments [Member] \| Other Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	14.60%								14.60%