Note 4 - Vessels - Vessels and Vessel Improvements (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Vessels and vessel improvements at end of period	$ 662,179,523	$ 567,592,950
Vessels and Vessel Improvements [Member]
Purchase of Vessels and Vessel Improvements	121,331,815
Transfer to vessels held for sale	(15,210,204)
Vessel depreciation expense	(13,461,924)
Vessels and vessel improvements at end of period	$ 662,179,523	567,592,950
Advance paid for purchase of Singapore Eagle at December 31, 2016		$ 1,926,886