NOTES PAYABLE AND LEASE OBLIGATIONS - Weighted Average Lease Term and Discount Rate (Details)	Dec. 31, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Operating lease, weighted average remaining lease term	6 years 8 months 12 days	6 years 9 months 18 days
Finance lease, weighted average remaining lease term	3 years 6 months	3 years 8 months 12 days
Operating lease, weighted average discount rate, percent	2.00%	2.10%
Finance lease, weighted average discount rate, percent	1.50%	1.50%