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REVENUE (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2004
REVENUE [Abstract]
Number of vessels were employed on spot market during the period			15
Total number of vessels	20	17	17	3
Number of vessels temporarily operated directly in the spot market	6	6	0
Number of vessels were employed on bareboat charters			2
Net pool spot market earnings, cooperative arrangements	$ 77,287,000	$ 76,618,000	$ 119,598,000
Gross pool spot market earnings, Orion Tankers pool	36,339,000	0	0
Gross spot market earnings, through spot charters	17,056,000	18,169,000	0
Bareboat revenues	0	0	6,818,000
Total Voyage Revenues	130,682,000	94,787,000	126,416,000
Number of tankers withdrawn from pool	9
Concentration Risk [Line Items]
Accounts receivable	10,000	17,600,000
Orion Tankers Pool [Member]
Concentration Risk [Line Items]
Accounts receivable, net related party	$ 12,900,000	$ 1,600,000
Voyage Revenues [Member] | Gemini Tankers LLC [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	2.00%	97.00%	78.00%
Voyage Revenues [Member] | Orion Tankers Pool [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	98.00%	3.00%
Voyage Revenues [Member] | Stena Pool [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)			17.00%
Accounts Receivable [Member] | Gemini Tankers LLC [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)		99.00%	100.00%
Accounts Receivable, Net Related Party [Member] | Orion Tankers Pool [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	100.00%	100.00%

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The total number of tankers withdrawn from pool during the period, which may include crude oil tankers and new vessels under construction to be used in the normal conduct of business and not intended for resale.

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Amount of receivables arising from transactions with related parties due within one year or the normal operating cycle, if longer.

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