RIGHT-OF-USE ASSETS AND OPERATING LEASE LIABILITIES - OPERATING LEASE EXPENSE (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating lease expense:
Total operating lease expense	$ 1,753	$ 1,781
Cash paid for amounts included in the measurement of operating lease liabilities	1,838	1,803
Short-term lease payments not included in the measurement of lease liabilities	$ 13	15
Weighted average remaining term in years	7 years 10 months 28 days		8 years 7 days
Weighted average discount rate	3.44%		3.46%
Related Party
Operating lease expense:
Variable lease expense	$ 1,182	1,158
Fixed lease expense	10	23
Third Party
Operating lease expense:
Variable lease expense	180	224
Fixed lease expense	368	361
Short-term lease expense	$ 13	$ 15