LEASES - Lease Cost (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Apr. 01, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Components of lease expense:
Operating lease cost (resulting from lease payments)		$ 3,154	$ 2,912	$ 9,281	$ 8,605
Acquisitions		$ 0	0	$ 0	0
Weighted average remaining lease term of operating leases		9 years 7 months 6 days		9 years 7 months 6 days		10 years 4 months 24 days
Weighted average discount rate of operating leases		3.10%		3.10%		3.28%
Supplemental cash flow information related to leases:
Operating cash flows from operating leases		$ 4,158	2,349	$ 10,160	6,653
Operating lease ROU assets		67,554		67,554		$ 69,320
Lease Liability		77,506		77,506		$ 76,871
Revere acquisition
Components of lease expense:
Acquisitions	$ 7,400	$ 0	$ 0	$ 7,720	$ 0
Supplemental cash flow information related to leases:
Lease Liability	$ 8,700