Fair Value Of Financial Instruments, Derivative And Marketable Securities (Notional And Fair Value Of Derivative Instruments) (Details)	12 Months Ended				12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 JPY (¥)	Dec. 31, 2013 JPY (¥)	Dec. 31, 2012 Interest Rate Swap - LT [Member] USD ($) item	Dec. 31, 2013 Interest Rate Swap - LT [Member] JPY (¥)	Dec. 31, 2013 Other Liabilities [Member] Interest Rate Swap - LT [Member] USD ($)		Dec. 31, 2012 Other Liabilities [Member] Interest Rate Swap - LT [Member] USD ($)		Dec. 31, 2013 Current Assets [Member] Foreign Exchange Contracts [Member] USD ($)	Dec. 31, 2012 Current Assets [Member] Foreign Exchange Contracts [Member] USD ($)	Dec. 31, 2013 Current Liabilities [Member] Foreign Exchange Contracts [Member] USD ($)	Dec. 31, 2012 Current Liabilities [Member] Foreign Exchange Contracts [Member] USD ($)	Dec. 31, 2013 Oslo Bulk AS [Member]	Dec. 31, 2012 Oslo Bulk AS [Member]	Jul. 31, 2011 Oslo Bulk AS [Member]	Dec. 31, 2009 Oslo Bulk AS [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives, current notional amount											$ 1,800,000	$ 1,700,000
Liability derivatives, current notional amount							46,713,000	[1]	74,207,000	[2]				6,000,000
Derivatives, current notional amount	48,513,000	81,907,000
Asset derivatives, fair value	39,000	147,000									39,000	147,000
Liability derivatives, fair value	(4,472,000)	(7,940,000)					(3,724,000)	[1]	(7,683,000)	[2]			(748,000)	(257,000)
Notional amount under contract	46,700,000	61,500,000
Exchange rate			86.74	102.53		105.31
Original funding of vessel's delivery cost (in hundredths)	80.00%	80.00%	80.00%
Revised funding of vessel's delivery cost (in hundredths)	65.00%	65.00%	65.00%
Reduction in funding of vessel's delivery cost (in hundredths)	15.00%	15.00%	15.00%
Change in fair value related to ineffective portion of derivative instrument, gain	362,000	87,000
Repayments of lines of credit			686,318,979
Negative balance related to an interest rate swap in Oslo Bulk AS	(659,000)	(1,000,000)
Ownership percentage (in hundredths)															25.00%	25.00%	25.00%	25.00%
Loss on early payment of loan					$ 571,000
Number of pure car trucks					2

[1] We have outstanding a variable-to-fixed interest rate swap with respect to a Yen-based facility for the financing of a PCTC delivered in March 2010. The notional amount under this contract is approximately $46.7 million (based on a Yen to USD exchange rate of 105.31 as of December 31, 2013).  With the bank exercising its option to reduce the underlying Yen loan from 80% to 65% funding of the vessel’s delivery cost, the 15% reduction represents the ineffective portion of this swap, which consists of the portion of the derivative instrument that is no longer supported by underlying borrowings.  The change in fair value related to the ineffective portion of this swap was a $362,000 gain for the year ended December 31, 2013 and this amount was included in earnings. The fair value balance as of December 31, 2013, includes a negative $659,000 balance related to an interest rate swap from our 25% investment in Oslo Bulk AS.

[2] We have outstanding a variable-to-fixed interest rate swap with respect to a Yen-based facility for the financing of a PCTC delivered in March 2010. The notional amount under this contract is approximately $61.5 million (based on a Yen to USD exchange rate of 86.74 as of December 31, 2012).  With the bank exercising its option to reduce the underlying Yen loan from 80% to 65% funding of the vessel’s delivery cost, the 15% reduction represents the ineffective portion of this swap, which consists of the portion of the derivative instrument that is no longer supported by underlying borrowings.  The change in fair value related to the ineffective portion of this swap was a $87,000 gain for the year ended December 31, 2012 and this amount was included in earnings. We paid down this facility in January 2012 in an amount of Yen 686,318,979 to bring our Asset Maintenance Loan to Value Facility requirement in line. The fair value balance as of December 31, 2012, includes a negative $1.0 million balance related to an interest rate swap from our 25% investment in Oslo Bulk AS. Also included in earnings is a $571,000 loss, related to the early pay-off of loans relating to two of our Pure Car Truck Carriers that were part of our recent Sale Leasebacks.