ACQUISITIONS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Nov. 12, 2021	Dec. 31, 2020	Dec. 31, 2018
Assets
Goodwill	$ 985,072		$ 506,206	$ 506,206
Blue Hills Bancorp, Inc. [Member]
Assets
Cash		$ 798,470
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Investments		266
Loans		4,908,949
Business Combination, Acquired Receivables, Estimated Uncollectible		(16,540)
Premises and equipment		66,825
Goodwill		478,866
Core deposit intangible		10,300
Other assets		125,543
Total assets acquired		6,372,679
Liabilities
Deposits		4,440,432
Borrowings		576,088
Other liabilities		46,432
Total liabilities assumed		5,062,952
Purchase price		$ 1,309,727