FAIR VALUE OF FINANCIAL INSTRUMENTS, DERIVATIVES AND MARKETABLE SECURITIES (Details)	3 Months Ended	12 Months Ended						12 Months Ended														12 Months Ended										12 Months Ended								12 Months Ended
	Dec. 31, 2012 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 JPY (¥)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2011 Corporate Bonds [Member] USD ($)	Dec. 31, 2011 Mutual Funds [Member] USD ($)	Dec. 31, 2012 Swap 1 [Member] USD ($)	Dec. 31, 2012 Swap 2 [Member] USD ($)	Dec. 31, 2012 Swap 3 [Member] USD ($)		Dec. 31, 2012 Foreign Exchange Contract 1 [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contract 2 [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contract 3 [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contract 4 [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contract 5 [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contract 6 [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contract 7 [Member] USD ($)	Dec. 31, 2012 Oslo Bulk AS [Member]	Jul. 31, 2011 Oslo Bulk AS [Member]	Dec. 31, 2009 Oslo Bulk AS [Member]	Dec. 31, 2012 Accumulated Other Comprehensive Loss [Member] USD ($)	Dec. 31, 2011 Accumulated Other Comprehensive Loss [Member] USD ($)	Dec. 31, 2012 Interest Rate Swaps [Member] USD ($)	Dec. 31, 2011 Interest Rate Swaps [Member] USD ($)	Dec. 31, 2012 Interest Rate Swaps [Member] Interest Expense [Member] USD ($)	Dec. 31, 2011 Interest Rate Swaps [Member] Interest Expense [Member] USD ($)	Dec. 31, 2012 Interest Rate Swap - ST [Member] USD ($)	Dec. 31, 2011 Interest Rate Swap - ST [Member] USD ($)	Dec. 31, 2012 Interest Rate Swap - ST [Member] Current Liabilities [Member] USD ($)	Dec. 31, 2011 Interest Rate Swap - ST [Member] Current Liabilities [Member] USD ($)	Dec. 31, 2012 Interest Rate Swap - LT [Member] USD ($)		Dec. 31, 2011 Interest Rate Swap - LT [Member] USD ($)		Dec. 31, 2012 Interest Rate Swap - LT [Member] Other Liabilities [Member] USD ($)		Dec. 31, 2011 Interest Rate Swap - LT [Member] Other Liabilities [Member] USD ($)		Dec. 31, 2012 Foreign Exchange Contracts [Member] USD ($)	Dec. 31, 2011 Foreign Exchange Contracts [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contracts [Member] Other Revenues [Member] USD ($)	Dec. 31, 2011 Foreign Exchange Contracts [Member] Other Revenues [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contracts [Member] Other Current Assets [Member] USD ($)	Dec. 31, 2012 Foreign Exchange Contracts [Member] Current Liabilities [Member] USD ($)	Dec. 31, 2011 Foreign Exchange Contracts [Member] Other Assets [Member] USD ($)
FAIR VALUE OF FINANCIAL INSTRUMENTS, DERIVATIVES AND MARKETABLE SECURITIES [Abstract]
Maximum potential future exposure on derivatives	$ 6,800,000	$ 6,800,000
Derivatives, Fair Value [Line Items]
Equity investee ownership interest (in hundredths)																			25.00%	25.00%	25.00%
Unrealized loss related to derivative instruments included in accumulated other comprehensive loss																						7,400,000	8,600,000
Asset derivatives, current notional amount																																								1,700,000	2,400,000
Liability derivatives, current notional amount																												0	12,845,000			74,207,000	[1]	140,455,000	[2]					6,000,000
Derivatives, current notional amount	81,907,000	81,907,000		155,700,000
Asset derivatives, fair value	147,000	147,000		202,000																								0	0			0	[1]	0	[2]									147,000		202,000
Liability derivatives, fair value	(7,940,000)	(7,940,000)		(9,446,000)																										0	(545,000)					(7,683,000)	[1]	(8,901,000)	[2]	0	0				(257,000)
Derivative fair value of derivative liability negative balance																																1,003,619
Loss on early payment of loan																																571,000
Number of pure car trucks																																2
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in Other Comprehensive Income		1,243,000		101,000																				1,486,000	72,000															(243,000)	29,000
Amount of Gain(Loss) Reclassified from AOCI to Income		(3,286,000)		(3,548,000)																						(3,106,000)	(3,982,000)															(180,000)	434,000
Gain(Loss) Recognized in Income from Ineffective portion		(485,000)		(101,000)																				(485,000)	(101,000)															0	0
Derivative [Line Items]
Effective Date								Sep. 26, 2005	Sep. 26, 2005	Mar. 15, 2009
Termination Date								Sep. 28, 2015	Sep. 28, 2015	Sep. 15, 2020
Current Notional Amount	74,206,901	74,206,901		74,839,660				6,333,333	6,333,333	61,540,235	[3]
Swap Rate (in hundredths)								4.41%	4.41%	2.065%
Type								Fixed	Fixed	Fixed
Exchange rate				76.92						86.74		13.7787	14.2939	14.5700	80.00	81.02	85.16	85.27
Original funding of vessel's delivery cost (in hundredths)				80.00%						80.00%
Revised funding of vessel's delivery cost (in hundredths)				65.00%						65.00%
Reduction in funding of vessel's delivery cost (in hundredths)	15.00%	15.00%	15.00%	15.00%
Change in fair value related to ineffective portion of derivative instrument				101,000						87,000
Repayments of lines of credit			686,318,979
Number of foreign currency derivatives held	7	7	7
Notional amount of forward purchase contracts												750,000	250,000	700,000	1,500,000	1,500,000	1,500,000	1,500,000
Projected Peso exposure represented by Mexican Peso foreign exchange contracts (in hundredths)	60.00%	60.00%	60.00%
Transaction Date												May 31, 2012	May 31, 2012	May 31, 2012	Nov. 30, 2012	Nov. 30, 2012	Dec. 31, 2012	Dec. 31, 2012
Transaction Amount	7,700,000	7,700,000										750,000	250,000	700,000	1,500,000	1,500,000	1,500,000	1,500,000
Effective Date												Jan. 31, 2013	Jan. 31, 2013	Jun. 30, 2013	Nov. 30, 2012	Nov. 30, 2012	Dec. 31, 2012	Dec. 31, 2012
Expiration Date												May 31, 2013	May 31, 2013	Dec. 31, 2013	Mar. 31, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
Long term debt carrying amount	237,630,000	237,630,000		322,093,000
Schedule of Available-for-sale Securities [Line Items]
Marketable securities gain	447,000
Gain on sale of investments	580,000	580,000		(747,000)	213,000
Available-for-sale Securities [Abstract]
Cost Basis				12,699,000		8,553,000	4,146,000
AOCI Unrealized Holding Gains				128,000		70,000	58,000
Estimated Fair Value				12,827,000		8,623,000	4,204,000
Impairment charges		$ 0		$ 0	$ 0

[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 $61,540,235 (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 $1,003,619 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.

[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 $74,839,660 (based on a Yen to USD exchange rate of 76.92 as of December 31, 2011). 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 $101,000 loss for the year ended December 31, 2011 and this amount was included in earnings.

[3] *Notional Amount converted from Yen at December 31, 2012 at a Yen to USD exchange rate of 86.74