RIGHT-OF-USE ASSETS AND OPERATING LEASE LIABILITIES - OPERATING LEASE EXPENSE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating lease expense:
Total operating lease expense	$ 7,217	$ 7,379	$ 7,177
Cash paid for amounts included in the measurement of operating lease liabilities	$ 7,286	$ 7,254	7,175
Short-term lease payments not included in the measurement of lease liabilities			62
Weighted average remaining term in years	7 years 6 months 25 days	8 years 4 months 13 days
Weighted average discount rate	3.05%	3.10%
Related Party
Operating lease expense:
Variable lease expense	$ 4,921	$ 4,885	4,690
Fixed lease expense	137	91	37
Third Party
Operating lease expense:
Variable lease expense	787	786	883
Fixed lease expense	$ 1,372	$ 1,617	1,505
Short-term lease expense			$ 62