RIGHT-OF-USE ASSETS AND OPERATING LEASE LIABILITIES - OPERATING LEASE EXPENSE (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Operating lease expense:
Total operating lease expense	$ 7,177
Cash paid for amounts included in the measurement of operating lease liabilities	7,175
Short-term lease payments not included in the measurement of lease liabilities	$ 62
Weighted average remaining term in years	8 years 7 days
Weighted average discount rate	3.46%
Related Party
Operating lease expense:
Variable lease expense	$ 4,690
Fixed lease expense	37
Third Party
Operating lease expense:
Variable lease expense	883
Fixed lease expense	1,505
Short-term lease expense	$ 62