BORROWINGS (Details) - USD ($) $ in Thousands	Sep. 30, 2016		Dec. 31, 2015
Debt Instrument [Line Items]
Repurchase Agreements	$ 233,483	[1]	$ 215,041
Total short-term borrowings	489,749		477,852
Long-term Federal Home Loan Bank Advances	10,000		30,000
Total long-term borrowings	10,808		35,911
Short-term Debt [Member]
Debt Instrument [Line Items]
Repurchase Agreements	228,464		184,989
FHLBB advances less than 90 days	240,000		255,000
FHLBB and correspondent bank overnight borrowings	16,200		12,800
Capital lease obligation	66		63
Long-term Debt [Member]
Debt Instrument [Line Items]
Repurchase Agreements	0		5,052
Capital lease obligation	808		859
Commercial and Industrial Sector [Member] | Short-term Debt [Member]
Debt Instrument [Line Items]
Repurchase Agreements	$ 5,019		$ 25,000

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