Note 3 - Vessel Acquisitions and Dispositions - Vessels Additions (Details) - Vessel [Member] - Americas [Member] - Hercules [Member]	6 Months Ended
	Jun. 30, 2016 Boe T
Vessels Additions, Year Built	2016
Vessels Additions, Length	286
Vessels Additions, Brake Horsepower | Boe	10,960	[1]
Vessels Additions, Deadweight Tons | T	5,300	[2]
Vessels Additions, Month Delivered	Jun-16

[1] BHP - Brake Horsepower

[2] DWT - Deadweight Tons