SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Impairment (Details) $ in Thousands			3 Months Ended		6 Months Ended
	Oct. 10, 2019 USD ($)	Aug. 02, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2020 item	Feb. 24, 2020 item
Impairment of long-lived assets
Impairment of vessel assets			$ 0	$ 13,897	$ 112,814	$ 13,897
Net proceeds from sale of vessels					14,726	6,309
Genco Picardy, Genco Predator, Genco Provence and Genco Warrior
Impairment of long-lived assets
Number impaired vessel assets | item							4
Impairment of vessel assets					27,046
Baltic Hare, Baltic Fox, Baltic Wind, Baltic Cove, Baltic Breeze, Genco Ocean, Genco Bay, Genco Avra, Genco Mare and Genco Spirit
Impairment of long-lived assets
Number of vessels to be disposed | item								10
Impairment of vessel assets					$ 85,768
Baltic Wind, Baltic Breeze and Genco Bay
Impairment of long-lived assets
Number of vessels to be disposed | item							3
Genco Challenger
Impairment of long-lived assets
Impairment of vessel assets				4,401		4,401
Sale of assets	$ 5,250	$ 5,250
Broker commission (as a percent)	2.00%	2.00%
Adjusted net sales price of vessel				5,145		5,145
Genco Champion and Genco Charger
Impairment of long-lived assets
Impairment of vessel assets				$ 9,496		$ 9,496