VESSELS, OTHER PROPERTY AND DEFERRED DRYDOCK (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	Nov. 20, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Disposal group, not discontinued operation, gain (loss) on disposal		$ 5,847	$ 7,353	$ 0	$ 0	$ (6,623)	$ (97,782)	$ (113)	$ (14)	$ (13,200)	$ (104,532)	$ (207)
Vessel/Fleet [Member]
Property, Plant and Equipment [Line Items]
Cost of ATB sold	$ 1,055
Commissions payable to broker-dealers and clearing organizations	27
Disposal group, not discontinued operation, gain (loss) on disposal	$ 7,322
Property, plant and equipment weighted average age										10 years 24 days
Exit Financing Facilities [Member] | Equipment [Member] | 8 ATBs and 3 Handysize Product Carriers [Member]
Property, Plant and Equipment [Line Items]
Debt instrument, collateral amount		$ 307,163								$ 307,163