BORROWINGS (Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Long-term Debt	$ 74,906	$ 0
Total Long-Term Borrowings	187,355	110,901
Subordinated Debt	49,601	34,728
Junior Subordinated Debentures [Member] \| Capital Trust V Preferred Securities Due in 2037 [Member]
Debt Instrument [Line Items]
Long-term Debt	51,547
Total Long-Term Borrowings	51,507	51,505
Junior Subordinated Debentures [Member] \| Slades Ferry Trust I Preferred Securities Due in 2034 [Member]
Debt Instrument [Line Items]
Long-term Debt		10,234
Total Long-Term Borrowings	0
Junior Subordinated Debentures [Member] \| Central Bancorp Capital Trust I Securities Due in 2034 [Member]
Debt Instrument [Line Items]
Long-term Debt	5,258
Total Long-Term Borrowings	5,258	5,258
Junior Subordinated Debentures [Member] \| Central Bancorp Capital Trust II Securities Due in 2037 [Member]
Debt Instrument [Line Items]
Long-term Debt	6,083
Total Long-Term Borrowings	6,083	6,083
Junior Subordinated Debentures [Member] \| East Main Street Trust [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 0	$ 3,093

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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