DEBT (Debt Modification, Repurchases and Extinguishment) (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Mar. 31, 2020	Jan. 28, 2020	Jan. 23, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Interest Expense	$ 10,200	$ 15,100	$ 17,300	$ 26,300
Gain (Loss) on extinguishment of debt			(1,014)	0
Other income/(expense)	143	839	(13,289)	1,875
Amortization of Issuance, Deferred Financing Costs, Commitments, Administrative and Other Fees for Debt Facilities [Member]
Debt Instrument [Line Items]
Interest Expense	8,700	$ 17,100	20,600	$ 34,400
2017 Debt Facilities [Member]
Debt Instrument [Line Items]
Other income/(expense)			(13,500)
2017 Term Loan, ABN Term Loan Facility and 10.75% Subordinated Notes [Member]
Debt Instrument [Line Items]
Write off of deferred debt issuance cost			12,500
2020 Debt Facilities [Member]
Debt Instrument [Line Items]
Deferred finance costs, gross	7,300		7,300
Core Revolving Facility [Member]
Debt Instrument [Line Items]
Long-term line of credit						$ 20,000
Core Term Loan Facility and Transition Term Loan Facility [Member]
Debt Instrument [Line Items]
Deferred finance costs, gross	$ 6,300		6,300
Payments of financing costs			$ 6,500
Core Term Loan Facility and Transition Term Loan Facility Deemed Expensed [Member]
Debt Instrument [Line Items]
Deferred finance costs, gross					$ 200
10.75% Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt instrument, repurchase amount						$ 27,900
Debt instrument, interest rate, stated percentage	10.75%		10.75%
Revolving Credit Facility [Member] | INSW Facilities [Member]
Debt Instrument [Line Items]
Deferred finance costs, gross								$ 300
Revolving Credit Facility [Member] | Core Revolving Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							$ 40,000
Deferred finance costs, gross	$ 900		$ 900
Secured Debt [Member] | 2020 Debt Facilities [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							390,000
Term Loan [Member] | Core Term Loan Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							300,000
Term Loan [Member] | Core Revolving Facility [Member]
Debt Instrument [Line Items]
Deferred finance costs, gross	800		800
Term Loan [Member] | Transition Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity							$ 50,000
Subordinated Debt [Member] | 10.75% Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt instrument prepayment fee amount	$ 1,000		$ 1,000
Debt instrument, interest rate, stated percentage	10.75%		10.75%					10.75%