LEASES - Future minimum lease payments under finance leases and operating leases - (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jan. 01, 2019
Finance leases
2020	$ 619
2021	1,250
2022	926
2023	309
2024	31
2025 and thereafter	4
Total lease payments	3,139
Less - portion representing interest	(338)
Present value of lease obligations	2,801
Less - Current portion of lease obligations	(1,032)	$ (546)
Long-term portion of lease obligations	1,769	673
Operating Leases
2020	1,751
2021	3,387
2022	2,902
2023	2,884
2024	2,906
2025 and thereafter	20,118
Total lease payments	33,948
Less - portion representing interest	(12,435)
Present value of lease obligations	21,513		$ 19,508
Less - current portion of lease obligations	(1,582)	(1,326)
Non-current operating lease liabilities	19,931	$ 16,591
Total
2020	2,370
2021	4,637
2022	3,828
2023	3,193
2024	2,937
2025 and thereafter	20,122
Total lease payments	37,087
Less - portion representing interest	(12,773)
Present value of lease obligations	24,314
Less - current portion of lease obligations	(2,614)
Long-term portion of lease obligations	$ 21,700