INDEBTEDNESS - Facility components (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current debt, net of deferred financing costs	$ 15,182	$ 13,243
Non-current debt, net of deferred financing costs and current component	189,525	172,443
Term Loan and DDTL [Member]
Current borrowing on debt	15,617	13,691
Deferred financing costs	(435)	(448)
Current debt, net of deferred financing costs	15,182	13,243
Non-current borrowing on debt	158,623	165,755
Deferred financing costs	(598)	(812)
Non-current debt, net of deferred financing costs and current component	$ 158,025	$ 164,943