LEASES - Summary of Leases (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Components of lease expense:
Operating lease cost (resulting from lease payments)	$ 2,707	$ 3,047	$ 8,211	$ 9,333
Supplemental cash flow information related to leases:
Operating cash flows from operating leases	2,866	3,208	8,698	9,762
ROU assets obtained in the exchange for lease liabilities due to new leases and acquisitions	$ 0	0	$ 0	803
Operating lease, right-of-use asset, statement of financial position	Other assets		Other assets		Other assets
Operating lease, liability, statement of financial position	Accrued interest payable and other liabilities		Accrued interest payable and other liabilities		Accrued interest payable and other liabilities
Supplemental balance sheet information related to leases:
Operating lease ROU assets	$ 51,302		$ 51,302		$ 57,872
Operating lease liabilities	$ 59,962		$ 59,962		$ 67,138
Other information related to leases:
Weighted average remaining lease term of operating leases	8 years 7 months 6 days		8 years 7 months 6 days		9 years
Weighted average discount rate of operating leases	2.97%		2.97%		2.92%
Revere Bank And RPJ
Supplemental cash flow information related to leases:
ROU assets obtained in the exchange for lease liabilities due to new leases and acquisitions	$ 0	$ 0	$ 0	$ 0