Significant Accounting Policies - Lease Expense (Details)	12 Months Ended
	Dec. 31, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Sub lease income from chartered-in contracts greater than 12 months *	$ 10,259,768
Voyage charters
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Sub lease income from chartered-in contracts greater than 12 months *	5,600,000
Charter hire expenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease expense for chartered-in contracts less than 12 months	28,805,970
Operating lease, expense	13,362,672
Lease cost	42,168,642
General and administrative expenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease, expense	$ 719,698