DEBT - $400 Million Credit Facility (Details)			12 Months Ended
	Nov. 14, 2016 USD ($)	Nov. 10, 2016 USD ($) item	Dec. 31, 2016 USD ($)	Jun. 08, 2016 USD ($)	Dec. 31, 2015 USD ($)
Line of Credit Facility [Line Items]
PIK interest			$ 800,000
Restricted cash non-current			27,426,000		$ 315,000
Secured Debt | $400 Million Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 400,000,000	400,000,000	$ 400,000,000
Proceeds from Issuance of Secured Debt	$ 400,000,000		400,000,000
Number of vessels mortgaged | item		45
Number of remaining vessels to be sold | item		5
Number of vessels contracted to be sold			3
Remaining borrowing capacity			0
Total outstanding including PIK interest			392,833,000		0
PIK interest (as a percent)		1.50%
PIK interest		$ 800,000	800,000
Prepayment under cash sweep required		0
Restricted cash non-current			11,180,000		$ 0
Repayment of the outstanding debt
2017			400,000
2018			400,000
2019			30,440,000
2020			30,440,000
2021			339,120,000
Total debt			400,800,000
Secured Debt | $400 Million Credit Facility | Through December 31, 2018
Line of Credit Facility [Line Items]
Amortization payments per quarter		100,000
Minimum cash balance required per vessel owned		$ 250,000
Cash flow sweep (as a percent)		100.00%
Secured Debt | $400 Million Credit Facility | From March 31, 2019 through December 31, 2020
Line of Credit Facility [Line Items]
Amortization payments per quarter		$ 7,610,000
Secured Debt | $400 Million Credit Facility | From March 31, 2021 through September 30, 2021
Line of Credit Facility [Line Items]
Amortization payments per quarter		18,571,000
Secured Debt | $400 Million Credit Facility | Period Upon Final Maturity On November 15 2021
Line of Credit Facility [Line Items]
Amortization payments per quarter		$ 282,605,000
Secured Debt | $400 Million Credit Facility | From June 30, 2018 to December 30, 2018
Line of Credit Facility [Line Items]
Collateral security maintenance test (as a percent)		105.00%
Secured Debt | $400 Million Credit Facility | From December 31, 2018 to December 30, 2020
Line of Credit Facility [Line Items]
Collateral security maintenance test (as a percent)		115.00%
Vessel age repayment period		15 years
Cash flow sweep (as a percent)		75.00%
Cash flow sweep option one (as a percent)		$ 50
Threshold initial aggregate prepayments limit for prepayment under cash sweep		$ 10,000,000
Secured Debt | $400 Million Credit Facility | After December 30, 2020
Line of Credit Facility [Line Items]
Collateral security maintenance test (as a percent)		135.00%
Secured Debt | $400 Million Credit Facility | From January 1, 2019 To December 31, 2019
Line of Credit Facility [Line Items]
Minimum cash balance required per vessel owned		$ 400,000
Secured Debt | $400 Million Credit Facility | After January 1, 2020
Line of Credit Facility [Line Items]
Minimum cash balance required per vessel owned		$ 700,000
Secured Debt | $400 Million Credit Facility | LIBOR
Line of Credit Facility [Line Items]
Applicable margin over reference rate (as a percent)		3.75%
Secured Debt | Minimum | $400 Million Credit Facility
Line of Credit Facility [Line Items]
Minimum working capital required			$ 0
Secured Debt | Maximum | $400 Million Credit Facility
Line of Credit Facility [Line Items]
Maximum total indebtedness to total capitalization			0.70%