ACQUISITIONS (Details Textual) - USD ($) $ in Thousands			12 Months Ended
	Nov. 12, 2021	Apr. 01, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Acquisition Related Costs			$ 40,840		$ 26,433
Business Combination, Pro Forma Information [Abstract]
Contractual cash flows not expected to be collected	$ 16,540
Financing Receivable, Credit Loss, Expense (Reversal)			18,205	$ 52,500	$ 6,000
Blue Hills Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Number of shares of company stock issued for each share of Central common stock (in shares)	0.2750
Business transaction value	$ 1,300,000
Cost of acquired entity, cash paid		$ 11,200
Increase in acquirer outstanding shares	14,300,000
Acquisition Related Costs			40,800
Loans acquired	$ 4,908,949
Business Combination, Pro Forma Information [Abstract]
Contractual cash flows not expected to be collected	(16,540)
Financing Receivable, Credit Loss, Expense (Reversal)	$ 50,700
Combination of INDB and Blue Hills Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Acquisition Related Costs			$ 42,200