Loans, Allowance for Loan Losses and Credit Quality (Modifications which occurred during the period & change in recorded investment) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017 USD ($) contract	Sep. 30, 2016 USD ($) contract	Sep. 30, 2017 USD ($) contract	Sep. 30, 2016 USD ($) contract
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract	7	8	44	37
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 815	$ 1,373	$ 6,222	$ 4,931
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 815	$ 1,373	$ 6,236	$ 4,973
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract	1	0	9	7
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 196	$ 0	$ 1,575	$ 528
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 196	$ 0	$ 1,575	$ 528
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract	0	3	6	9
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 0	$ 986	$ 1,884	$ 2,329
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 986	$ 1,884	$ 2,329
Small Business [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract	2	1	10	3
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 183	$ 59	$ 447	$ 168
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 183	$ 59	$ 447	$ 168
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract	0	0	5	5
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 0	$ 0	$ 889	$ 1,167
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 0	$ 0	$ 900	$ 1,209
Consumer Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract	4	4	14	8
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment	$ 436	$ 328	$ 1,427	$ 632
Financing Receivable, Modifications, Post-Modification Recorded Investment	$ 436	$ 328	$ 1,430	$ 632
Consumer - Other [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract		0		5
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment		$ 0		$ 107
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 0		$ 107