Subsequent Events (Details) - USD ($)				3 Months Ended		6 Months Ended
	Jul. 29, 2019	Jul. 18, 2019	Jul. 15, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Proceeds from sale of vessels						$ 22,631,367	$ 9,719,013
Gain on sale of vessels				$ 966,802	$ 105,073	$ 5,073,349	$ 105,073
Common stock, shares authorized (in shares)				700,000,000		700,000,000		700,000,000
Subsequent Event
Property, Plant and Equipment [Line Items]
Common stock, shares authorized (in shares)	8,000,000
Subsequent Event | Jefferies Capital Services LLC | Affiliated Entity
Property, Plant and Equipment [Line Items]
Commons stock available to affiliate (in shares)	3,582,880
Subsequent Event | Convertible Senior Notes due 2024 | Convertible Debt
Property, Plant and Equipment [Line Items]
Debt instrument, face amount	$ 114,100,000
Stated interest rate	5.00%
Net proceeds	$ 112,000,000
Conversion premium	17817.37%
Conversion premium per principal amount of notes	$ 1,000
Conversion price (in dollars per share)	$ 5.61
Subsequent Event | Convertible Senior Notes due 2024 | Convertible Debt | Oaktree Capital Management L.P.
Property, Plant and Equipment [Line Items]
Debt instrument, face amount	$ 45,500,000
Subsequent Event | Convertible Senior Notes due 2024 | Convertible Debt | GoldenTree Asset Management LP
Property, Plant and Equipment [Line Items]
Debt instrument, face amount	$ 23,600,000
Subsequent Event | Kestrel Vessel
Property, Plant and Equipment [Line Items]
Proceeds from sale of vessels		$ 7,300,000
Gain on sale of vessels		$ 1,000,000
Subsequent Event | SDARI-64 Ultramax Dry Bulk Vessel
Property, Plant and Equipment [Line Items]
Total consideration			$ 122,000,000