Equity Offerings (Details) $ / shares in Units, shares in Millions			9 Months Ended
	Jan. 20, 2017 USD ($)	Dec. 13, 2016 USD ($) vessel $ / shares shares	Sep. 30, 2017 USD ($) $ / shares	Sep. 30, 2016 USD ($)	Dec. 31, 2016 $ / shares
Subsidiary, Sale of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares			$ 0.01		$ 0.01
Net proceeds from issuance of stock | $			$ 96,030,003	$ 85,700,535
December Private Placement
Subsidiary, Sale of Stock [Line Items]
Issuance of shares for private placement (in shares) | shares		22.2
Common stock, par value (in dollars per share) | $ / shares		$ 0.01
Common Stock, purchase price (in dollars per share) | $ / shares		$ 4.50
Gross proceeds from issuance of stock | $		$ 100,000,000
Net proceeds from issuance of stock | $	$ 96,000,000
Ultramax Vessels
Subsidiary, Sale of Stock [Line Items]
Number of vessels acquired | vessel		2