LEASES - Summary of Operating Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 8,808	$ 8,421	$ 17,658	$ 16,912
Operating cash flow - Operating leases			18,303	16,545
New ROU assets - Operating leases			$ 4,964	$ 6,922
Weighted average remaining lease term - Operating leases	5 years 4 months 24 days	6 years 1 month 6 days	5 years 4 months 24 days	6 years 1 month 6 days
Weighted average discount rate - Operating leases	9.40%	10.30%	9.40%	10.30%
Third-Party
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 7,959	$ 7,576	$ 15,962	$ 15,221
Related-Party
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 849	$ 845	$ 1,696	$ 1,691