DELIVERY AND DISPOSAL OF VESSELS (Details) - USD ($) $ in Thousands														3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 15, 2017	Sep. 09, 2017	Sep. 01, 2017	Aug. 15, 2017	Aug. 09, 2017	Aug. 07, 2017	Aug. 01, 2017	Jun. 13, 2017	May 13, 2017	Feb. 01, 2017	Dec. 19, 2016	Aug. 25, 2016	Aug. 05, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
DELIVERY OF VESSELS
Accounts payable and accrued expenses														$ 26,907		$ 26,907		$ 33,991
Assets held for sale														31,530		31,530		30,195
Loss on disposal of vessels, net														36,941	$ 10,756	114,644	$ 10,177
Gener8 Ulysses
DELIVERY OF VESSELS
Gross proceeds from sale of vessel										$ 30,500
Assets held for sale																		30,200
Loss on disposal of vessels, net																		6,900
Gener8 Elektra
DELIVERY OF VESSELS
Gross proceeds from sale of vessel				$ 10,500
Loss on disposal of vessels, net														1,000		5,900
Gener8 Orion
DELIVERY OF VESSELS
Gross proceeds from sale of vessel								$ 13,000
Loss on disposal of vessels, net																10,100
Gener8 Daphne
DELIVERY OF VESSELS
Gross proceeds from sale of vessel									$ 10,500
Loss on disposal of vessels, net																5,100
Gener8 Noble
DELIVERY OF VESSELS
Gross proceeds from sale of vessel	$ 81,000
Loss on disposal of vessels, net																25,400
Gener8 Theseus
DELIVERY OF VESSELS
Gross proceeds from sale of vessel						$ 81,000
Loss on disposal of vessels, net																31,900
Gener8 Spyridon
DELIVERY OF VESSELS
Gross proceeds from sale of vessel											$ 13,900
Loss on disposal of vessels, net																		7,100
Genmar Vision
DELIVERY OF VESSELS
Gross proceeds from sale of vessel													$ 28,000
Loss on disposal of vessels, net																		3,200
Genmar Victory
DELIVERY OF VESSELS
Gross proceeds from sale of vessel												$ 29,000
Loss on disposal of vessels, net																		$ 7,300
Gener8 Phoenix and Gener8 Horn
DELIVERY OF VESSELS
Loss on disposal of vessels, net														16,200		16,200
Gener8 Phoenix
DELIVERY OF VESSELS
Gross proceeds from sale of vessel					$ 7,800
Gener8 Horn
DELIVERY OF VESSELS
Gross proceeds from sale of vessel							$ 8,000
Korean Export Credit Facility | Gener8 Hector | Gener8 Hector LLC
DELIVERY OF VESSELS
Borrowings under term loan facilities																49,500
Korean Export Credit Facility | Gener8 Ethos | Gener8 Ethos LLC
DELIVERY OF VESSELS
Borrowings under term loan facilities																50,631
Korean Export Credit Facility | Gener8 Noble
DELIVERY OF VESSELS
Repayments of debt	$ 50,400
Korean Export Credit Facility | Gener8 Theseus
DELIVERY OF VESSELS
Repayments of debt						$ 50,100
Refinancing Facility | Gener8 Ulysses
DELIVERY OF VESSELS
Repayments of debt										$ 20,000
Refinancing Facility | Gener8 Elektra
DELIVERY OF VESSELS
Repayments of debt				$ 7,600
Refinancing Facility | Gener8 Orion
DELIVERY OF VESSELS
Repayments of debt								$ 11,100
Refinancing Facility | Gener8 Daphne
DELIVERY OF VESSELS
Repayments of debt									$ 8,100
Refinancing Facility | Gener8 Spyridon
DELIVERY OF VESSELS
Repayments of debt											$ 11,700
Refinancing Facility | Genmar Vision
DELIVERY OF VESSELS
Repayments of debt													$ 19,400
Refinancing Facility | Genmar Victory
DELIVERY OF VESSELS
Repayments of debt												$ 19,400
Refinancing Facility | Gener8 Phoenix
DELIVERY OF VESSELS
Repayments of debt		$ 7,600
Refinancing Facility | Gener8 Horn
DELIVERY OF VESSELS
Repayments of debt			$ 8,200
2017 Asset Under Construction
DELIVERY OF VESSELS
Accounts payable and accrued expenses														$ 0		$ 0