RIGHT-OF-USE ASSETS AND OPERATING LEASE LIABILITIES - OPERATING LEASE EXPENSE (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Operating lease expense:
Total operating lease expense	$ 1,790	$ 5,327
Cash paid for amounts included in the measurement of operating lease liabilities	1,795	5,372
Short-term lease payments not included in the measurement of lease liabilities	$ 14	$ 40
Weighted average remaining term in years	8 years 1 month 24 days	8 years 1 month 24 days
Weighted average discount rate	3.48%	3.48%
Related Party
Operating lease expense:
Variable lease expense	$ 1,164	$ 3,478
Fixed lease expense	10	28
Third Party
Operating lease expense:
Variable lease expense	210	644
Fixed lease expense	392	1,137
Short-term lease expense	$ 14	$ 40