Equipment Acquisitions, Dispositions and Depreciation and Impairment Policies (Narrative) (Details) (USD $)	9 Months Ended										12 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 U.S.-flag Product Tankers [Member] equipment	Sep. 30, 2014 Offshore Support Vessels Crew [Member] equipment	Sep. 30, 2014 Offshore Support Vessels Supply [Member] equipment	Sep. 30, 2014 Liftboats [Member] equipment	Sep. 30, 2014 Wind Farm Utility Vessel [Member] equipment	Sep. 30, 2014 Inland River Dry Cargo Barges [Member] equipment	Sep. 30, 2014 Inland River Towboat [Member] equipment	Sep. 30, 2014 R O R O Vessels [Member] equipment	Dec. 31, 2013 R O R O Vessels [Member] equipment	Sep. 30, 2014 Aircraft [Domain]	Sep. 30, 2014 Gains on Asset Dispositions and Impariments, Net [Member]
Property, Plant and Equipment [Line Items]
Payments to Acquire Property, Plant, and Equipment	$ 311,094,000	$ 146,483,000	$ 151,000,000
Unrecorded Unconditional Purchase Obligation, Maximum Quantity			3
Number Of Equipments Delivered				3	2		1	65	1		1
Number Of Equipments Sold			1	6	4	1	1	60	3	1
Sales Price Of Equipment	207,700,000
Proceeds from Sale of Property, Plant and Equipment, Excluding Deposits on Future Equipment Sales	182,100,000
Proceeds from Issuance of Secured Debt	25,600,000
Proceeds from disposition of property and equipment	5,800,000
Gain (Loss) on Disposition of Property Plant Equipment	93,000,000
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property													39,200,000
Deferred Gains on Asset Sales	53,832,000	14,609,000
Amortization Of Deferred Gains Included In Gains On Asset Dispositions And Impairments, Net	(3,484,000)	(2,146,000)											3,500,000
Asset Impairment Charges												$ 3,900,000