Recent Accounting Pronouncements - Operating Lease Assets and Liabilities (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 17,185,019	$ 20,410,037	$ 20,410,037
Current portion of operating lease liabilities	13,346,261	13,255,978	13,255,978
Lease liabilities - long term	$ 4,821,044	$ 8,301,793	8,301,793
Discount rate	5.48%
Minimum
Lessee, Lease, Description [Line Items]
Discount rate	5.05%
Maximum
Lessee, Lease, Description [Line Items]
Discount rate	6.08%
Weighted Average
Lessee, Lease, Description [Line Items]
Discount rate	5.50%
Chartered-in contracts greater than 12 months
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 15,370,956		18,442,965
Current portion of operating lease liabilities	12,700,708		12,622,524
Lease liabilities - long term	$ 3,659,302		6,974,943
Discount rate	5.37%
Office leases
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 1,814,063		1,967,072
Current portion of operating lease liabilities	645,553		633,454
Lease liabilities - long term	$ 1,161,742		$ 1,326,850
Discount rate	5.80%