Significant Accounting Policies - Additional Information (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) t	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)	Jan. 01, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Restricted cash	$ 5,500,000				$ 10,900,000				$ 5,500,000	$ 10,900,000
Write off of allowance for doubtful accounts									900,000	1,400,000	$ 3,400,000
Provision for doubtful accounts									1,300,000	0
Certificates of deposit											4,500,000
Asset impairment charges									$ 0	0	0
Amortization period for vessels over fifteen years old									30 months
Age of vessels									15 years
Amortization period for vessels less than fifteen years old									60 months
Deferred financing costs - Super Senior Facility	166,111				285,342				$ 166,111	285,342
Vessel useful lives									3 years
Accumulated deficit	437,074,354				415,377,239				$ 437,074,354	415,377,239
Operating lease right-of-use assets	20,410,037								20,410,037			$ 28,705,002
Fair value below contract value of time charters acquired	0				1,818,114				0	1,818,114
Revenue earned as demurrage	71,486,350	$ 74,110,376	$ 69,391,315	$ 77,389,597	86,692,209	$ 69,092,740	$ 74,938,700	$ 79,370,609	292,377,638	310,094,258	$ 236,784,625
Deferred costs	400,000				$ 800,000				400,000	800,000
Lease liability	$ 21,557,771								$ 21,557,771
Minimum
Property, Plant and Equipment [Line Items]
Term of contract	30 days								30 days
Maximum
Property, Plant and Equipment [Line Items]
Term of contract	2 years								2 years
Voyage In Progress
Property, Plant and Equipment [Line Items]
Revenue earned as demurrage									$ 13,100,000	$ 12,000,000.0
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Property, Plant and Equipment [Line Items]
Accumulated deficit													$ 800,000
Accounting Standards Update 2016-02
Property, Plant and Equipment [Line Items]
Operating lease right-of-use assets												30,500,000
Fair value below contract value of time charters acquired												1,800,000
Lease liability												$ 30,500,000
Vessels
Property, Plant and Equipment [Line Items]
Scrap value of vessels | t									300
Super Senior Revolver Facility | Revolving Credit Facility
Property, Plant and Equipment [Line Items]
Proceeds from lines of credit									$ 0
Letter of Credit
Property, Plant and Equipment [Line Items]
Restricted cash and cash equivalents	$ 100,000								$ 100,000