Vessel Acquisitions and Dispositions (Details 3) (Clwyd Supporter [Member], North Sea [Member], SpV [Member])	3 Months Ended
	Mar. 31, 2012 hp DWT ft
Clwyd Supporter [Member] | North Sea [Member] | SpV [Member]
Vessels Held for Sale (Textual) [Abstract]
Year Built	1984
Length (feet)	266
Breakhorse Power	10,700
Deadweight Tons	1,350