BORROWINGS (Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total Long-Term Borrowings	$ 110,901	$ 107,755
Subordinated Debt	34,728	34,682
Junior Subordinated Debentures [Member] | Capital Trust V Preferred Securities Due in 2037 [Member]
Debt Instrument [Line Items]
Total Long-Term Borrowings	51,505	51,503
Junior Subordinated Debentures [Member] | Slades Ferry Trust I Preferred Securities Due in 2034 [Member]
Debt Instrument [Line Items]
Total Long-Term Borrowings	10,234	10,229
Junior Subordinated Debentures [Member] | Central Bancorp Capital Trust I Securities Due in 2034 [Member]
Debt Instrument [Line Items]
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]
Total Long-Term Borrowings	6,083	6,083
Junior Subordinated Debentures [Member] | East Main Street Trust [Member]
Debt Instrument [Line Items]
Total Long-Term Borrowings	$ 3,093	$ 0