LEASES - Undiscounted future lease payments for operating and finance leases (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Operating Leases
2021 (excluding the nine-months ended September 30, 2021)	$ 892
2022	3,207
2023	2,423
2024	1,887
2025	1,600
2026 and thereafter	11,588
Total lease payments	21,597
Less imputed interest	(3,386)
Total	18,211	$ 20,513
Finance Leases
2021 (excluding the nine-months ended September 30, 2021)	713
2022	871
2023	21
2024	13
2025	8
Total lease payments	1,626
Less imputed interest	(9)
Total	$ 1,617	$ 823