Revenues (Details) - USD ($)	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Revenues.
Voyage charter revenues	$ 14,864,184	$ 8,189,289
Time charter revenues	5,372,203	7,374,365
Other revenues	95,514	290,186
Total revenues	20,331,901	15,853,840
Profit-sharing sharing revenue	$ 0	$ 3,200,000