Revenues (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues.
Net pool revenues—related party	$ 20,468,380	$ 20,837,311	$ 48,943,739	$ 58,496,696
Time charter revenues	12,507,394	12,465,684	25,072,049	24,998,035
Voyage charter revenues	1,733,247		1,733,247
Other revenues, net	20,000	308,238	5,458	632,278
Total revenues	$ 34,729,021	$ 33,611,233	$ 75,754,493	$ 84,127,009