DEBT - $108 Million Credit Facility (Details) $ in Thousands		3 Months Ended		9 Months Ended
	Aug. 14, 2018 USD ($) item	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)	Jul. 12, 2018 item	Jun. 06, 2018 item
Agreement To Purchase Ultramax And Capesize Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement | item								4
Agreement to Purchase Capesize Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement | item							2	2
Agreement To Purchase Ultramax Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement | item								2
Secured Debt | $108 Million Credit Facility
Line of Credit Facility
Term of facilities	5 years
Maximum borrowing capacity	$ 108,000	$ 108,000	$ 108,000	$ 108,000	$ 108,000	$ 108,000
Proceeds from credit facility			$ 108,000		108,000
Maximum facility amount of fair market value of aggregate vessels at delivery (as a percent)			45.00%
Remaining borrowing capacity		0		0
Repayment of secured debt		1,580	$ 0	4,740	$ 0
Long-term debt		$ 100,127		$ 100,127		$ 104,571
Repaid value of loan when certain debt terms are met	$ 0
Average age of collateral vessels for repayment of loan	20 years
Amount of repayment per quarter	$ 1,580
Percentage limit of consolidated net income for which dividends can be paid	50.00%
Key covenant - Unrestricted cash and cash equivalents minimum	$ 30,000
Key covenant – Percentage of unrestricted cash to total indebtedness	7.50%
Minimum working capital required	$ 0
Maximum total indebtedness to total capitalization (as a ratio)	0.70
Secured Debt | $108 Million Credit Facility | LIBOR | Through September 30, 2019
Line of Credit Facility
Applicable margin over reference rate (as a percent)	2.50%
Secured Debt | $108 Million Credit Facility | Agreement To Purchase Ultramax And Capesize Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement | item	6
Secured Debt | $108 Million Credit Facility | Agreement to Purchase Capesize Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement | item	4
Secured Debt | $108 Million Credit Facility | Agreement To Purchase Ultramax Drybulk Vessels
Line of Credit Facility
Number of vessels committed to be acquired under purchase agreement | item	2
Secured Debt | Minimum | $108 Million Credit Facility
Line of Credit Facility
Collateral security maintenance test (as a percent)	135.00%
Secured Debt | Minimum | $108 Million Credit Facility | LIBOR | Period After September 30, 2019
Line of Credit Facility
Applicable margin over reference rate (as a percent)	2.25%
Secured Debt | Maximum | $108 Million Credit Facility
Line of Credit Facility
Collateral security maintenance test (as a percent)	200.00%
Secured Debt | Maximum | $108 Million Credit Facility | LIBOR | Period After September 30, 2019
Line of Credit Facility
Applicable margin over reference rate (as a percent)	2.75%