Vessel Acquisitions and Dispositions (Details 2) (Americas [Member], Crew [Member])	3 Months Ended
	Mar. 31, 2012 ft DWT hp
Bluefin [Member]
Vessels Dispositions
Year Built	2008
Length (feet)	165
Breakhorse Power	7,200
Deadweight Tons	337
Month disposed	2012-01
Sailfish [Member]
Vessels Dispositions
Year Built	2007
Length (feet)	176
Breakhorse Power	7,200
Deadweight Tons	307
Month disposed	2012-05
Swordfish [Member]
Vessels Dispositions
Year Built	2009
Length (feet)	176
Breakhorse Power	7,200
Deadweight Tons	307
Month disposed	2012-05