LEASES - Summary of Operating Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 8,594	$ 8,573	$ 26,253	$ 25,485
Operating cash flow - Operating leases			26,556	25,329
New ROU assets - Operating leases			$ 9,893	$ 10,885
Weighted average remaining lease term - Operating leases	5 years 3 months 18 days	6 years	5 years 3 months 18 days	6 years
Weighted average discount rate - Operating leases	9.10%	10.10%	9.10%	10.10%
Third-Party
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 8,043	$ 8,567	$ 24,604	$ 22,947
Related-Party
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 551	$ 6	$ 1,649	$ 2,538