Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenues, net	$ 292,377,638	$ 310,094,258	$ 236,784,625
Voyage expenses	87,701,407	79,566,452	62,351,252
Vessel expenses	82,342,123	81,336,260	78,607,244
Charter hire expenses	42,168,642	38,045,778	31,283,956
Depreciation and amortization	40,545,904	37,717,462	33,690,686
General and administrative expenses	35,041,996	36,156,660	33,126,310
Other operating expense	1,125,000	0	0
Gain on sale of vessels	(5,978,566)	(335,160)	(2,134,767)
Total operating expenses, net	282,946,506	272,487,452	236,924,681
Operating income/(loss)	9,431,132	37,606,806	(140,056)
Interest expense	30,577,489	25,743,531	29,376,994
Interest expense	(1,867,326)	(585,168)	(651,069)
Other expense/(income)	149,632	(126,241)	(37,905)
Loss on debt extinguishment	2,268,452	0	14,968,609
Total other expense, net	31,128,247	25,032,122	43,656,629
Net (loss)/income	$ (21,697,115)	$ 12,574,684	$ (43,796,685)
Weighted average shares outstanding:
Basic (in shares)	71,365,618	70,665,212	69,182,302
Diluted (in shares)	71,365,618	71,802,173	69,182,302
Per share amounts:
Basic net (loss)/income (in dollars per share)	$ (0.30)	$ 0.18	$ (0.63)
Diluted net (loss)/income (in dollars per share)	$ (0.30)	$ 0.18	$ (0.63)