LEASES - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Components of lease expense:
Operating lease cost (resulting from lease payments)	$ 3,151	$ 2,730
ROU assets obtained in the exchange for lease liabilities due to new leases and acquistions	$ 803	0
Weighted average remaining lease term of operating leases	9 years 4 months 24 days		9 years 6 months
Weighted average discount rate of operating leases	2.97%		3.04%
Supplemental cash flow information related to leases:
Operating cash flows from operating leases	$ 3,280	2,082
Operating lease ROU assets	64,455		$ 65,215
Lease liability	74,219		$ 74,982
Revere Bank And RPJ
Components of lease expense:
ROU assets obtained in the exchange for lease liabilities due to new leases and acquistions	$ 0	$ 311