Loans, Allowance for Loan Losses and Credit Quality (Details 11) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Interest income recognized on impaired loans
Average Recorded Investment	$ 74,830	$ 70,959	$ 76,814	$ 73,282
Interest Income Recognized	986	1,088	2,982	3,097
WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	31,541	34,584	32,840	35,539
Interest Income Recognized	466	582	1,407	1,611
WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	43,289	36,375	43,974	37,743
Interest Income Recognized	520	506	1,575	1,486
Commercial and Industrial [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	7,553	8,181	7,762	8,584
Interest Income Recognized	91	107	275	323
Commercial and Industrial [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	2,360	1,077	2,684	1,487
Interest Income Recognized	30	23	96	74
Commercial Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	15,175	18,625	15,638	19,033
Interest Income Recognized	262	329	788	1,005
Commercial Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	24,984	17,444	25,128	18,103
Interest Income Recognized	330	255	1,013	790
Commercial Construction [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,105		1,441
Interest Income Recognized	13		39
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	1,479	1,461	1,631	1,543
Interest Income Recognized	26	25	79	79
Small Business [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	624	1,176	652	1,171
Interest Income Recognized	10	16	30	49
Residential Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	2,159	2,709	2,221	2,730
Interest Income Recognized	24	81	68	84
Residential Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	13,773	13,592	13,884	13,720
Interest Income Recognized	135	168	391	434
Consumer - Home Equity [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	3,570	3,527	3,604	3,571
Interest Income Recognized	41	39	126	117
Consumer - Home Equity [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	575	803	585	815
Interest Income Recognized	6	14	18	41
Consumer - Other [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	500	81	543	78
Interest Income Recognized	9	1	32	3
Consumer - Other [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	973	2,283	1,041	2,447
Interest Income Recognized	$ 9	$ 30	$ 27	$ 98