OPERATING LEASES - Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease right-of-use assets	$ 30,007	$ 18,289
Total leased assets	30,007	18,289
Current portion of lease liabilities	6,097	3,701
Long-term lease liabilities	24,962	15,320
Total lease liabilities	$ 31,059	$ 19,021