BORROWINGS (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Repurchase Agreements	$ 210,055	$ 237,984
Total short-term borrowings	210,055	268,809
Long-term Federal Home Loan Bank Advances	25,000	10,000
Total long-term borrowings	25,000	10,000
Short-term Debt [Member]
Debt Instrument [Line Items]
Repurchase Agreements	210,055	237,984
FHLBB advances less than 90 days	0	25,000
FHLBB and Correspondent Bank Overnight Borrowings	$ 0	$ 5,825