Loans, Allowance for Loan Losses and Credit Quality (Details 11) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest income recognized on impaired loans
Average Recorded Investment	$ 73,494	$ 61,311	$ 74,346	$ 62,598
Interest Income Recognized	999	913	2,005	1,838
WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	36,259	28,261	36,875	28,570
Interest Income Recognized	539	463	1,082	935
WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	37,235	33,050	37,471	34,028
Interest Income Recognized	460	450	923	903
Commercial and Industrial [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	8,396	6,401	8,836	6,490
Interest Income Recognized	114	85	230	172
Commercial and Industrial [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	3,076	1,343	3,221	1,398
Interest Income Recognized	43	28	89	60
Commercial Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	18,392	20,214	18,448	20,407
Interest Income Recognized	312	350	628	707
Commercial Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	18,242	15,685	18,235	16,432
Interest Income Recognized	263	229	526	473
Commercial Construction [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,608		1,608
Interest Income Recognized	13		26
Commercial Construction [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment
Interest Income Recognized
Small Business [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,393	1,474	1,454	1,517
Interest Income Recognized	22	25	46	52
Small Business [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	748	1,043	760	1,082
Interest Income Recognized	12	16	23	32
Residential Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	2,236		2,253
Interest Income Recognized	25		44
Residential Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	13,688	12,958	13,732	13,053
Interest Income Recognized	127	157	255	296
Consumer - Home Equity [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	3,674	100	3,691	100
Interest Income Recognized	43	2	85	3
Consumer - Home Equity [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	407	240	410	241
Interest Income Recognized	5	4	10	8
Consumer - Other [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	560	72	585	56
Interest Income Recognized	10	1	23	1
Consumer - Other [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,074	1,781	1,113	1,822
Interest Income Recognized	$ 10	$ 16	$ 20	$ 34