VESSEL ACQUISITIONS AND DISPOSITIONS (Details) - USD ($) $ in Thousands												3 Months Ended		9 Months Ended
	May 16, 2017	Mar. 19, 2017	Feb. 16, 2017	Feb. 09, 2017	Jan. 09, 2017	Dec. 12, 2016	Nov. 04, 2016	Oct. 26, 2016	Oct. 21, 2016	Oct. 20, 2016	May 17, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Nov. 10, 2016	Dec. 31, 2014	Aug. 12, 2010
Line of Credit Facility | $148 Million Credit Facility
VESSEL ACQUISITIONS
Face amount of term loan facility													$ 148,000		$ 148,000			$ 148,000
Secured Debt | $100 Million Term Loan Facility
VESSEL ACQUISITIONS
Repayment of secured debt													1,923		5,769
Face amount of term loan facility													100,000		100,000				$ 100,000
Secured Debt | $400 Million Credit Facility
VESSEL ACQUISITIONS
Repayment of secured debt												$ 100	$ 0	$ 300	$ 0
Face amount of term loan facility												$ 400,000		$ 400,000		$ 400,000	$ 400,000
Genco Prosperity
VESSEL ACQUISITIONS
Sale of assets	$ 3,050
Broker commission (as a percent)	3.50%
Genco Success
VESSEL ACQUISITIONS
Sale of assets		$ 2,800
Broker commission (as a percent)		3.00%
Genco Carrier
VESSEL ACQUISITIONS
Sale of assets			$ 3,560
Brokerage commission			$ 92
Genco Reliance
VESSEL ACQUISITIONS
Sale of assets				$ 3,500
Broker commission (as a percent)				3.50%
Genco Wisdom
VESSEL ACQUISITIONS
Sale of assets					$ 3,250
Broker commission (as a percent)					3.50%
Genco Acheron
VESSEL ACQUISITIONS
Sale of assets						$ 3,480
Broker commission (as a percent)						5.50%
Genco Leader
VESSEL ACQUISITIONS
Sale of assets							$ 3,470
Broker commission (as a percent)							3.00%
Genco Leader | Line of Credit Facility | $148 Million Credit Facility
VESSEL ACQUISITIONS
Repayment of secured debt							$ 3,366
Face amount of term loan facility							$ 148,000
Genco Pioneer
VESSEL ACQUISITIONS
Sale of assets								$ 2,650
Broker commission (as a percent)								5.50%
Genco Pioneer | Line of Credit Facility | $148 Million Credit Facility
VESSEL ACQUISITIONS
Repayment of secured debt								$ 2,504
Face amount of term loan facility								$ 148,000
Genco Sugar
VESSEL ACQUISITIONS
Sale of assets										$ 2,450
Broker commission (as a percent)										5.50%
Genco Sugar | Secured Debt | $100 Million Term Loan Facility
VESSEL ACQUISITIONS
Repayment of secured debt									$ 2,315
Face amount of term loan facility									$ 100,000
Genco Marine
VESSEL ACQUISITIONS
Sale of assets											$ 2,187
Broker commission (as a percent)											2.00%