LEASES (Bareboat and Time Charters-In) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Leases [Line Items]
Total operating lease liabilities	$ 23,915	$ 30,911
Bareboat Charters-In [Member]
Leases [Line Items]
2020	3,165
2021	6,278
2022	6,278
2023	4,532
Total lease payments	20,253
less imputed interest	(2,229)
Total operating lease liabilities	$ 18,024
2020, operating days	368 days
2021, operating days	730 days
2022, operating days	730 days
2023, operating days	556 days
Operating days, total	2384 days
Time Charters-In [Member]
Leases [Line Items]
2020	$ 1,783
2021	2,170
Total lease payments	3,953
less imputed interest	(142)
Total operating lease liabilities	$ 3,811
2020, operating days	368 days
2021, operating days	408 days
Operating days, total	776 days