Loans, Allowance for Loan Losses and Credit Quality (Int Inc. Recognized on Impaired Loans by Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Interest income recognized on impaired loans
Average Recorded Investment	$ 44,558	$ 58,474	$ 45,318	$ 59,804
Interest Income Recognized	385	529	1,165	1,731
WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	23,672	25,077	24,169	25,908
Interest Income Recognized	226	194	695	661
WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	20,886	33,397	21,149	33,896
Interest Income Recognized	159	335	470	1,070
Commercial and Industrial [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	2,444	2,080	2,584	2,204
Interest Income Recognized	16	11	48	41
Commercial and Industrial [Member] \| WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	2,097	3,687	2,135	3,894
Interest Income Recognized	4	10	13	57
Commercial Real Estate [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	11,549	13,876	11,775	14,433
Interest Income Recognized	115	89	348	337
Commercial Real Estate [Member] \| WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	6,854	15,830	6,977	15,993
Interest Income Recognized	42	204	126	609
Construction Loans [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment		307		309
Interest Income Recognized		0		0
Small Business [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	646	465	679	484
Interest Income Recognized	5	4	18	14
Small Business [Member] \| WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	367	540	384	564
Interest Income Recognized	6	7	17	22
Residential Real Estate [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	4,255	3,566	4,286	3,601
Interest Income Recognized	42	42	134	123
Residential Real Estate [Member] \| WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	10,004	11,698	10,071	11,764
Interest Income Recognized	92	106	272	358
Consumer - Home Equity [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	4,616	4,585	4,677	4,670
Interest Income Recognized	45	44	138	134
Consumer - Home Equity [Member] \| WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,299	1,221	1,310	1,238
Interest Income Recognized	13	4	36	13
Consumer - Other [Member] \| WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	162	198	168	207
Interest Income Recognized	3	4	9	12
Consumer - Other [Member] \| WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	265	421	272	443
Interest Income Recognized	$ 2	$ 4	$ 6	$ 11

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

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