Condensed Consolidated Statements of Operations - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenues, net	$ 77,389,597	$ 79,370,609
Voyage expenses	25,906,140	22,514,592
Vessel expenses	20,093,706	21,078,657
Charter hire expenses	11,491,906	10,268,064
Depreciation and amortization	9,407,108	9,276,415
General and administrative expenses	8,409,919	9,913,964
Gain on sale of vessels	(4,106,547)	0
Total operating expenses	71,202,232	73,051,692
Operating income	6,187,365	6,318,917
Interest expense	6,762,003	6,261,069
Interest income	(434,318)	(95,276)
Loss on debt extinguishment	2,268,452	0
Other (income)/expense	(2,438,255)	100,379
Total other expense, net	6,157,882	6,266,172
Net income	$ 29,483	$ 52,745
Weighted average shares outstanding:
Basic (in shares)	71,283,301	70,452,814
Diluted (in shares)	72,070,868	71,531,864
Per share amounts:
Basic net income (in dollars per share)	$ 0.0000	$ 0.0000
Diluted net income (in dollars per share)	$ 0.0000	$ 0.0000