LEASES - Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
LEASES
Short-term lease cost	$ 51	$ 20	$ 176	$ 153
Operating lease cost	23,472	21,514	69,497	63,538
Total lease expense	$ 23,523	$ 21,534	$ 69,673	$ 63,691
Weighted-average remaining lease term - operating leases	5 years 6 months 14 days	3 years 8 months 12 days	5 years 6 months 14 days	3 years 8 months 12 days
Weighted-average discount rate - operating leases	3.69%	3.94%	3.69%	3.94%
Operating cash flows for operating leases			$ 68,614	$ 62,928