Fair Value Measurements (Fair Value Measurements Used in Testing Impairment of Long-lived Assets and Goodwill) (Details) $ in Thousands		1 Months Ended	3 Months Ended			12 Months Ended
		Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)		Dec. 31, 2015 USD ($) item		Dec. 31, 2014 USD ($) item
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment Loss						$ 154,463		$ 38,213
Impairment Losses, Intangible Assets, net			$ 400
Impairment Losses, Goodwill			(800)			2,735
Impairment Losses, Assets Held for Sale						154,463		38,213
Frascati Shops, Inc. and Tower, LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment Losses, Intangible Assets, net	[1]					(411)
Impairment Losses, Goodwill			(800)			(828)	[2]
Impairment Losses, Assets Held for Sale						(94,300)
United Ocean Services, LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment Losses, Intangible Assets, net			22,100			(22,129)	[3]
Impairment Losses, Goodwill						(1,900)
Handysize Vessel [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale			28,300	$ 48,701	[4]	28,300		48,701	[4]
Impairment Losses, Vessels, Property, and Other Equipment, net	[5]					$ (1,828)
Impairment Losses, Assets Held for Sale			3,300					$ (31,629)	[4]
Number of vessels held for sale | item						2		3
Inventory			600			$ 600
Handysize Vessel [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale	[4]			48,701				$ 48,701
ATB Barge And Tug Units [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale	[6]			6,976				6,976
Impairment Losses, Assets Held for Sale	[6]							(6,584)
ATB Barge And Tug Units [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale	[6]			6,976				$ 6,976
Tanker [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Number of vessels held for sale | item								1
Pure Car Truck Carriers [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Number of vessels held for sale | item						1
Other Assets Held for Sale [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale	[7]		51,846			$ 51,846
Impairment Losses, Assets Held for Sale	[7]					(94,241)
Other Assets Held for Sale [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale	[7]		51,846			51,846
Jones Act [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Vessels, Property, and Other Equipment, net	[8]		62,645			62,645
Impairment Losses, Vessels, Property, and Other Equipment, net	[8]					$ (22,675)
Number of vessels held for sale | item						1
Jones Act [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Vessels, Property, and Other Equipment, net	[8]		62,645			$ 62,645
Jones Act [Member] | United Ocean Services, LLC [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Impairment Losses, Goodwill		$ (1,900)				(1,907)	[9]
Jones Act [Member] | ATB Barge And Tug Units [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale			6,400			$ 6,400
Number of vessels held for sale | item						4
Jones Act [Member] | Harbor Tug [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Number of vessels held for sale | item						1
Specialty Contracts [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Vessels, Property, and Other Equipment, net	[10]		5,822			$ 5,822
Impairment Losses, Vessels, Property, and Other Equipment, net	[10]					(10,444)
Specialty Contracts [Member] | Level 3 Inputs [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Vessels, Property, and Other Equipment, net	[10]		$ 5,822			$ 5,822
Specialty Contracts [Member] | Tanker [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets Held for Sale				1,500				$ 1,500
Impairment Losses, Assets Held for Sale				$ (3,300)

[1] Refers to trade names and customer relations associated with our FSI acquisition, which is held for sale

[2] Refers to the goodwill associated with our FSI acquisition, which is held for sale.

[3] Refers to trade names and customer relations associated with our UOS acquisition included in the Jones Act segment.

[4] The loss of $31.6 million includes the loss related to three handysize vessels of approximately $28.3 million and a tanker of approximately $3.3 million that were written down to their fair market value less costs to sell. The tanker was sold during the fourth quarter of 2014. The assets held for sale balance of $48.7 million represents the three handysize vessels and their related equipment.

[5] Refers to impairments related to two handysize vessels that were reclassified from assets held for sale to held in use during 2015. The Strategic Plan identified these vessels for divestiture in the fourth quarter of 2015; accordingly, we reclassified these assets back to assets held for sale as of December 31, 2015 - see (1) above.

[6] The loss of $6.6 million is related to an ATB tug/barge unit, which was written down to its fair market value less costs to sell. The assets held for sale balance of $7.0 million consists of the ATB tug/barge unit of $6.4 million and $0.6 million of inventory associated with three handysize vessels that were held for sale.

[7] The loss of $94.2 million includes losses related to one PCTC, two handysize vessels, a capesize bulk carrier, a supramax bulk carrier, an ATB tug/barge unit, investments in chemical and asphalt tankers, FSI/Tower assets and the New Orleans office building, all of which were written down to their fair market value less costs to sell. The PCTC, one handysize vessel, the barge and the supramax bulk carrier were sold during the fourth quarter of 2015. The assets held for sale balance of $51.8 million represents the balance of the remaining assets.

[8] Refers to four ATB tug/barge units and a harbor tug in the Jones Act segment.

[9] Refers to the goodwill associated with our UOS acquisition included in the Jones Act segment.

[10] Refers to the ice strengthened multi-purpose vessel included in the Specialty Contracts segment.