LEASES - Schedule of Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Components of lease expense:
Operating lease cost (resulting from lease payments)	$ 12,304	$ 12,453
Supplemental cash flow information related to leases:
Operating cash flows from operating leases	12,930	13,571
ROU assets obtained in exchange for lease liabilities	803	871
Supplemental balance sheet information related to leases:
Operating lease ROU assets	57,872	65,215
Operating lease liabilities	$ 67,138	$ 74,982
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets	Other assets
Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]	Accrued interest payable and other liabilities	Accrued interest payable and other liabilities
Weighted average remaining lease term of operating leases	9 years	9 years 6 months
Weighted average discount rate of operating leases	2.92%	3.04%
Revere Bank and RPJ
Supplemental cash flow information related to leases:
ROU assets obtained in exchange for lease liabilities	$ 0	$ 7,720