LEASES - Balance Sheet Classifications (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease assets	$ 8,746	$ 10,528
Current portion of operating lease liabilities	3,302	3,195
Operating lease liabilities	5,444	7,333
Total lease liabilities	$ 8,746	$ 10,528