LEASES - LEASE COST (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021 USD ($) location	Sep. 30, 2020 USD ($) location	Sep. 30, 2021 USD ($) location	Sep. 30, 2020 USD ($) location
Leases [Abstract]
Operating lease cost	$ 3,635	$ 3,462	$ 10,529	$ 10,560
Finance lease cost:
Amortization of right-of-use assets	0	6	3	13
Interest on lease liabilities	0	1	1	3
Short-term lease cost	281	129	492	2,011
Variable lease cost	(9)	(89)	56	(133)
Sublease income	(91)	(89)	(274)	(267)
Total lease cost	3,816	3,420	10,807	12,187
Office rent expense	$ 500	$ 300	$ 1,300	$ 800
Number of office spaces, portion subleased \| location	1	1	1	1

Operating Lease, Expense, Office Rent

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Operating Lease, Number Of Office Spaces Subleased

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Amount of interest expense on finance lease liability.

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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 sublease income excluding finance and operating lease expense.

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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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