LEASES - Weighted average lease term and discount rate (Details)	Dec. 31, 2020	Dec. 31, 2019
LEASES
Operating leases	5 years 7 months 2 days	5 years 3 days
Finance leases	3 years 6 months 25 days	3 years 9 months 29 days
Operating leases	5.04%	5.54%
Finance leases	4.40%	4.51%