BALANCE SHEET OFFSETTING (Details) - USD ($) $ in Thousands		Jun. 30, 2020	Dec. 31, 2019
Offsetting Assets [Line Items]
Derivative Asset, Not Offset, Policy Election Deduction	[1],[2]	$ 0	$ 0
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Gross		53,447	18,239
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Liability		0	0
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed		53,447	18,239
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Not Offset, Policy Election Deduction	[1]	0	0
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Collateral, Obligation to Return Cash	[1]	(6,109)	(483)
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Amount Offset Against Collateral		47,338	17,756
Derivative Liability, Not Offset, Policy Election Deduction	[1]	0	0	[2]
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross		62,045	25,943
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Asset		0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned		62,045	25,943
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Not Offset, Policy Election Deduction	[1]	0	0
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Cash	[1]	62,045	25,429
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Amount Offset Against Collateral		0	514
Securities Sold under Agreements to Repurchase, Gross		195,998	237,984
Securities Sold under Agreements to Repurchase, Asset		0	0
Securities Sold under Agreements to Repurchase		195,998	237,984
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities	[1]	195,998	237,984
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Cash	[1]	0	0
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral		0	0
Customer Loan Swap Dealer Bank [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset			17,242
Derivative Asset, Fair Value, Gross Liability			0
Derivative Asset			17,242
Derivative, Collateral, Obligation to Return Cash	[1]		17,242
Derivative Asset, Fair Value, Amount Offset Against Collateral			0
Derivative Liability, Fair Value, Gross Liability		47,338
Derivative Liability, Fair Value, Gross Asset		0
Derivative Liability		47,338
Derivative Liability, Not Offset, Policy Election Deduction	[1]	0
Derivative, Collateral, Right to Reclaim Cash	[1]	47,338
Derivative Liability, Fair Value, Amount Offset Against Collateral		0
Customer Loan Swaps Commercial Customer [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	[2]	47,338	17,756
Derivative Asset, Fair Value, Gross Liability	[2]	0	0
Derivative Asset	[2]	47,338	17,756
Derivative, Collateral, Obligation to Return Cash	[1],[2]	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	[2]	47,338	17,756
Derivative Liability, Fair Value, Gross Liability	[2]		514
Derivative Liability, Fair Value, Gross Asset	[2]		0
Derivative Liability	[2]		514
Derivative, Collateral, Right to Reclaim Cash	[1],[2]		0
Derivative Liability, Fair Value, Amount Offset Against Collateral	[2]		514
Interest Rate Swap On Loans [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset		6,109
Derivative Asset, Fair Value, Gross Liability		0
Derivative Asset		6,109
Derivative, Collateral, Obligation to Return Cash	[1]	(6,109)
Derivative Asset, Fair Value, Amount Offset Against Collateral		0
FHLBB Advance Interest Rate Swap [Member]
Offsetting Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset			483
Derivative Asset, Fair Value, Gross Liability			0
Derivative Asset			483
Derivative, Collateral, Obligation to Return Cash	[1]		(483)
Derivative Asset, Fair Value, Amount Offset Against Collateral			0
Junior Subordinated Debt Interest Rate Swap [Member]
Offsetting Assets [Line Items]
Derivative Liability, Fair Value, Gross Liability		12,584	8,187
Derivative Liability, Fair Value, Gross Asset		0	0
Derivative Liability		12,584	8,187
Derivative, Collateral, Right to Reclaim Cash	[1]	12,584	8,187
Derivative Liability, Fair Value, Amount Offset Against Collateral		0	$ 0
Interest Rate Swap On Borrowings
Offsetting Assets [Line Items]
Derivative Liability, Fair Value, Gross Liability		2,123
Derivative Liability, Fair Value, Gross Asset		0
Derivative Liability		2,123
Derivative, Collateral, Right to Reclaim Cash	[1]	2,123
Derivative Liability, Fair Value, Amount Offset Against Collateral		$ 0

[1] (1) The amount presented was the lesser of the amount pledged (received) or the net amount presented in the consolidated statements of condition.

[2] (2) The Company manages its net exposure on its commercial customer loan swaps by obtaining collateral as part of the normal loan policy and underwriting practices.