Commitments and Contingencies - Narrative (Details)					1 Months Ended		12 Months Ended
	Dec. 09, 2018 t $ / d	May 04, 2018 t $ / d	May 10, 2017 USD ($) t $ / d	Oct. 15, 2015 USD ($)	Nov. 30, 2018 USD ($)	Oct. 31, 2014 t $ / d	Dec. 31, 2018 USD ($) option t	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 23, 2019 option	Dec. 21, 2018 USD ($)	Nov. 20, 2018 vessel	Sep. 04, 2018 USD ($) vessel	Aug. 14, 2018 USD ($)
Operating Leased Assets [Line Items]
Restricted cash							$ 74,917
Rent expense							$ 700,000	$ 700,000	$ 800,000
Carrying capacity (in dead weight tonnage) | t							2,705,764
Advance for vessel purchase							$ 2,040,000	$ 2,201,773	$ 1,926,886
Japanese Vessel
Operating Leased Assets [Line Items]
Carrying capacity (in dead weight tonnage) | t						37,000
Term of charter agreement						7 years
Charters agreement extension option						1 year
Vessel agreement termination fee			$ 1,500,000
Japanese Vessel | First Seven Years
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d						13,500
Japanese Vessel | Eighth Year Option
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d						13,750
2013 Built Japanese Vessel
Operating Leased Assets [Line Items]
Carrying capacity (in dead weight tonnage) | t			61,400
Term of charter agreement			4 years
Charters agreement extension option			2 years
2013 Built Japanese Vessel | First Four Years
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d			12,800
2013 Built Japanese Vessel | First Optional Year
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d			13,800
2013 Built Japanese Vessel | Second Optional Year
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d			14,300
Ultramax Vessels
Operating Leased Assets [Line Items]
Carrying capacity (in dead weight tonnage) | t		61,425
Term of charter agreement		3 years
Charters agreement extension option		2 years
Ultramax Vessels | First Optional Year
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d		13,750
Ultramax Vessels | Second Optional Year
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d		14,750
Ultramax Vessels | First Three Years
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d		12,700
2016 Built Ultramax Vessel
Operating Leased Assets [Line Items]
Carrying capacity (in dead weight tonnage) | t	62,487
Term of charter agreement	2 years
2016 Built Ultramax Vessel | First Two Years
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d	14,250
2016 Built Ultramax Vessel | Third Year Option
Operating Leased Assets [Line Items]
Vessel hire rate | $ / d	15,250
Ballast Water Treatment System
Operating Leased Assets [Line Items]
Projected project costs														$ 500,000
Advance for vessel purchase							1,000,000
Scrubber Systems
Operating Leased Assets [Line Items]
Projected project costs													$ 2,200,000
Advance for vessel purchase							$ 16,900,000
Number of scrubbers | vessel												15	19
Number of additional units to be purchased | vessel													18
Number of purchase options exercised | option							3
2015 Built Ultramax Vessel
Operating Leased Assets [Line Items]
Vessel purchase price											$ 20,400,000
Deposit paid on purchase of vessel							$ 2,000,000
Letter of Credit
Operating Leased Assets [Line Items]
Restricted cash				$ 74,917
Lease Agreement for Office Space in Stamford
Operating Leased Assets [Line Items]
Average annual rent expense				$ 400,000
Singapore Lease Arrangement
Operating Leased Assets [Line Items]
Average annual rent expense					$ 300,000
Maximum | Scrubber Systems
Operating Leased Assets [Line Items]
Number of scrubbers | vessel													37
Subsequent Event | Scrubber Systems
Operating Leased Assets [Line Items]
Number of purchase options exercised | option										3