LEASES AND RELATED PARTY LEASES - Supplemental Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
ROU assets	$ 89,174	$ 83,635
Current lease liabilities	13,987	12,818
Non-current lease liabilities	95,196	88,118
Total lease liabilities	109,183	$ 100,936
Leased facilities
Lessee, Lease, Description [Line Items]
Total lease liabilities	$ 109,183
Weighted average remaining lease term (in years)	11 years 3 months 18 days	11 years 7 months 6 days
Weighted average discount rate	5.00%	4.60%
Leased vehicles
Lessee, Lease, Description [Line Items]
Weighted average remaining lease term (in years)	2 years 3 months 18 days	2 years 3 months 18 days
Weighted average discount rate	2.70%	2.30%