LEASES (Bareboat and Time Charters-In) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Leases [Line Items]
Total operating lease liabilities	$ 26,386	$ 30,911
Bareboat Charters-In [Member]
Leases [Line Items]
2020	4,730
2021	6,278
2022	6,278
2023	4,532
Total lease payments	21,818
less imputed interest	(2,569)
Total operating lease liabilities	$ 19,249
2020, operating days	550 days
2021, operating days	730 days
2022, operating days	730 days
2023, operating days	556 days
Operating days, total	2566 days
Time Charters-In [Member]
Leases [Line Items]
2020	$ 3,111
2021	2,170
Total lease payments	5,281
less imputed interest	(215)
Total operating lease liabilities	$ 5,066
2020, operating days	643 days
2021, operating days	408 days
Operating days, total	1051 days