COMMITMENTS AND CONTINGENCIES - Components of Lease Expense (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Operating lease cost	$ 2,284	$ 1,874
Finance lease cost:
Amortization of right-of-use assets	1,169	1,210
Interest on lease liabilities	306	347
Total finance lease cost	1,475	1,557
Short-term lease cost	2,048	1,700
Variable lease cost	306	264
Total lease cost	$ 6,113	$ 5,395

Finance Lease, Cost, Total

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Finance Lease, Costs [Abstract]

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Amount of interest expense on finance lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
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Amount of amortization expense attributable to right-of-use asset from finance lease.

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Amount of lease cost recognized by lessee for lease contract.

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Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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