OTHER LIABILITIES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Current:
Deferred revenue	$ 24,114		$ 24,114		$ 9,451
Legal provisions	637		637		635
Derivative instruments	949		949		0
Operating lease liability	3,380		3,380		3,203
Other	200		200		226
Total other current liabilities	29,280		29,280		13,515
Non-current:
Deferred tax liabilities	23,062		23,062		21,294
Derivative instruments	11,326		11,326		12,670
Operating lease liability	8,503		8,503		8,434
Related party Guarantee Fee payable (Note 4)	33,465		33,465		33,465
Other	3,720		3,720		4,137
Total other non-current liabilities	80,076		80,076		$ 80,000
Deferred Revenue, Revenue Recognized	$ 2,400	$ 2,800	$ 5,800	$ 5,600