LEASES - Right-of-use lease assets and lease liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Right-of-use lease assets and lease liabilities
Operating right-of -use asset	$ 4,093	$ 4,001	$ 4,739
Current portion of operating lease liabilities	949	866	864
Long-term operating lease liabilities	3,358	3,344	4,044
Total operating lease liabilities	4,307		4,908
Finance right-of-use assets	4,742	4,778	4,641
Current portion of finance lease liabilities	4,693	4,728	4,616
Long-term finance lease liabilities	40	$ 44	17
Total finance lease liabilities	$ 4,733		$ 4,633