Recently Adopted Accounting Pronouncements - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues, net	$ 74,938,700	$ 53,631,224	$ 154,309,309	$ 99,486,281
Time charters
Disaggregation of Revenue [Line Items]
Revenues, net	37,355,472		66,678,691
Voyage charters
Disaggregation of Revenue [Line Items]
Revenues, net	$ 37,583,228		$ 87,630,618