BALANCE SHEET OFFSETTING (Details) - USD ($) $ in Thousands		Mar. 31, 2020		Dec. 31, 2019
Offsetting Assets [Line Items]
Derivative Asset, Not Offset, Policy Election Deduction	[1],[2]	$ 0	[3]	$ 0
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Gross		50,811		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		50,811		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]	(5,435)		(483)
Derivative Asset, Securities Purchased under Agreements to Resell, Securities Borrowed, Amount Offset Against Collateral		45,376		17,756
Derivative Liability, Not Offset, Policy Election Deduction	[1]	0	[3]	0	[2]
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Gross		59,477		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		59,477		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]	59,477		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		265,997		237,984
Securities Sold under Agreements to Repurchase, Asset		0		0
Securities Sold under Agreements to Repurchase		265,997		237,984
Derivative Liability, Securities Sold under Agreements to Repurchase, Securities Loaned, Collateral, Right to Reclaim Securities	[1]	265,997		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		45,220
Derivative Liability, Fair Value, Gross Asset		0
Derivative Liability		45,220
Derivative Liability, Not Offset, Policy Election Deduction	[1]	0
Derivative, Collateral, Right to Reclaim Cash	[1]	45,220
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]	45,220		17,756
Derivative Asset, Fair Value, Gross Liability	[2]	0		0
Derivative Asset	[2]	45,220		17,756
Derivative, Collateral, Obligation to Return Cash	[1],[2]	0		0
Derivative Asset, Fair Value, Amount Offset Against Collateral	[2]	45,220		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	[3]	5,591
Derivative Asset, Fair Value, Gross Liability	[3]	0
Derivative Asset	[3]	5,591
Derivative, Collateral, Obligation to Return Cash	[1],[3]	(5,435)
Derivative Asset, Fair Value, Amount Offset Against Collateral	[3]	156
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		12,642		8,187
Derivative Liability, Fair Value, Gross Asset		0		0
Derivative Liability		12,642		8,187
Derivative, Collateral, Right to Reclaim Cash	[1]	12,642		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	[3]	1,615
Derivative Liability, Fair Value, Gross Asset	[3]	0
Derivative Liability	[3]	1,615
Derivative, Collateral, Right to Reclaim Cash	[1],[3]	1,615
Derivative Liability, Fair Value, Amount Offset Against Collateral	[3]	$ 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.

[3] (3)Interest rate swap contracts were completed with same dealer bank. The Company maintains a master netting arrangement and settles collateral requested or pledged on a net basis for all contracts.