Allowance for Loan Losses and Credit Quality of Loans, Troubled Debt Restructurings (Details) (USD $)	9 Months Ended				3 Months Ended	9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Commercial Real Estate [Member]	Sep. 30, 2013 Home Equity [Member] Contract	Sep. 30, 2012 Commercial Loans [Member]	Sep. 30, 2013 Residential Real Estate Mortgages [Member] Contract	Sep. 30, 2013 Residential Real Estate Mortgages [Member] Contract	Sep. 30, 2012 Residential Real Estate Mortgages [Member] Contract	Sep. 30, 2012 Subsequent Default [Member] Home Equity [Member] Contract	Sep. 30, 2013 Subsequent Default [Member] Home Equity [Member]	Sep. 30, 2012 Subsequent Default [Member] Home Equity [Member]	Sep. 30, 2012 Commercial [Member] Contract	Sep. 30, 2013 Commercial Real Estate [Member] Contract	Sep. 30, 2013 Commercial Real Estate [Member] Contract	Sep. 30, 2013 Home Equity [Member] Contract	Sep. 30, 2013 Home Equity [Member] Subsequent Default [Member] Contract	Sep. 30, 2013 Home Equity [Member] Subsequent Default [Member] Contract	Sep. 30, 2012 Home Equity [Member] Subsequent Default [Member] Contract	Sep. 30, 2012 Commercial Loans [Member] Contract	Sep. 30, 2013 Residential Real Estate Mortgages [Member]	Sep. 30, 2012 Residential Real Estate Mortgages [Member] Subsequent Default [Member] Contract	Sep. 30, 2012 Residential Real Estate Mortgages [Member] Subsequent Default [Member] Home Equity [Member]	Sep. 30, 2012 Residential Real Estate Mortgages [Member] Home Equity [Member] Subsequent Default [Member] Contract
Financing Receivable, Modifications [Line Items]
Period of sustained repayment performance for nonperforming TDRs to be returned to performing status	6 months
Number of contracts			20		5	6	1	0			1	3	4	9	1	7	1	0		0		3
Pre-modification outstanding recorded investment		$ 7,000,000	$ 1,000,000	$ 1,000,000		$ 500,000	$ 200,000	$ 0	$ 500,000	$ 25,000		$ 6,100,000		$ 400,000	$ 100,000			$ 0	$ 300,000	$ 0	$ 400,000