VESSEL POOL ARRANGEMENTS (Details)	1 Months Ended		3 Months Ended										12 Months Ended
	May 31, 2013 item	Jul. 31, 2011 USD ($) item	Dec. 31, 2016 USD ($) item	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2011 USD ($) item	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) item
VLCC POOL Arrangements
Receivables from pool			$ 2,048,000				$ 13,611,000						$ 2,048,000	$ 13,611,000
Voyage revenues			102,361,000	$ 72,259,000	$ 105,958,000	$ 124,044,000	102,760,000	$ 89,291,000	$ 116,480,000	$ 121,402,000			404,622,000	429,933,000	$ 392,409,000
Working capital for 2011 VLCC pool			$ 1,900,000				1,900,000						$ 1,900,000	1,900,000
Navig8 Limited
VLCC POOL Arrangements
Ownership percentage in outstanding common shares (as a percent)			4.00%										4.00%
2011 VLCC Pool
VLCC POOL Arrangements
Working capital reserve fund required to be maintained by each vessel											$ 2,500,000	$ 2,000,000
Period to accumulate working capital reserve												8 months
Amount withheld from distributions of revenue earned per month												$ 250,000
2011 VLCC Pool | Two vessels entered into time charters
VLCC POOL Arrangements
Number of time charters entered into pool | item		2
Floor rate per day of time charter (in dollars)		$ 15,000
Profit share for daily rates above $30,000 (as a percent)		50.00%
Minimum floor rate for 50 percent profit share (in dollars)		$ 30,000
Number of vessels in which the VLCC Pool Operator maintains working capital reserve | item		2
2011 VLCC Pool | Five vessels directly admitted into pool
VLCC POOL Arrangements
Number of vessels directly admitted to pool | item												5
Working capital for 2011 VLCC pool							1,900,000							1,900,000	1,900,000
Number of time charters left the pool in which the Company continues to own and operation | item	5
2011 VLCC Pool | Five vessels directly admitted into pool | Other Assets
VLCC POOL Arrangements
Receivables from pool							$ 3,446,000							3,446,000	$ 3,446,000
Unique Tankers Pool
VLCC POOL Arrangements
Number of time charters entered into pool | item															17
Voyage revenues													$ 0	200,000	$ 300,000
Number of time charters remaining in pool | item			0										0
Unique Agency Fee														$ 2,200,000	$ 2,700,000