Vessels - Additional Information (Details)			3 Months Ended			9 Months Ended
	Sep. 02, 2020 USD ($)	Jul. 09, 2020 USD ($)	Sep. 30, 2020 USD ($) vessel	Jun. 30, 2020 USD ($) vessel	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) vessel	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($) vessel scrubber
Property, Plant and Equipment [Line Items]
Number of vessels | vessel			49			49
Loss on sale of vessels			$ 389,207		$ (971,129)	$ 389,207	$ (6,044,479)
Amount recorded in balance sheet						25,224,068	$ 50,537,160
Vessel Goldeneye
Property, Plant and Equipment [Line Items]
Agreed upon sales price		$ 4,600,000
Loss on sale of vessels			(100,000)
Vessel Skua
Property, Plant and Equipment [Line Items]
Agreed upon sales price	$ 5,100,000
Loss on sale of vessels			$ (300,000)			(300,000)
Scrubber Systems
Property, Plant and Equipment [Line Items]
Number of vessels | vessel				37
Projected project costs								$ 2,400,000
Amount recorded in balance sheet				$ 88,400,000
Scrubber Systems | Maximum
Property, Plant and Equipment [Line Items]
Number of scrubbers | scrubber								37
Ballast Water Treatment System
Property, Plant and Equipment [Line Items]
Number of vessels | vessel				18				39
Projected project costs								$ 500,000
Scrubbers and BWTS reclassified						2,800,000
Vessels and Vessel Improvements
Property, Plant and Equipment [Line Items]
Number of vessels | vessel								15
Amount recorded in balance sheet						6,800,000
Scrubbers and BWTS reclassified						$ 38,884,772