Loans Allowance for Credit Losses and Credit Quality (Details 7) (USD $)	Dec. 31, 2011 Contract
Troubled Debt Restructurings [Member]
Troubled Debt Restructurings
Number of Contracts	9
Pre-Modification Outstanding Recorded Investment	$ 3,202
Post-Modification Outstanding Recorded Investment	2,637
Troubled Debt Restructurings [Member] | Commercial [Member]
Troubled Debt Restructurings
Number of Contracts	3
Pre-Modification Outstanding Recorded Investment	840
Post-Modification Outstanding Recorded Investment	840
Troubled Debt Restructurings [Member] | Commercial real estate [Member]
Troubled Debt Restructurings
Number of Contracts	2
Pre-Modification Outstanding Recorded Investment	1,863
Post-Modification Outstanding Recorded Investment	1,298
Troubled Debt Restructurings [Member] | Residential real estate [Member]
Troubled Debt Restructurings
Number of Contracts	3
Pre-Modification Outstanding Recorded Investment	453
Post-Modification Outstanding Recorded Investment	453
Troubled Debt Restructurings [Member] | Consumer [Member]
Troubled Debt Restructurings
Number of Contracts	1
Pre-Modification Outstanding Recorded Investment	46
Post-Modification Outstanding Recorded Investment	46
Troubled Debt Restructurings that Subsequently Defaulted [Member]
Troubled Debt Restructurings
Number of Contracts	0
Recorded Investment	0
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Commercial [Member]
Troubled Debt Restructurings
Number of Contracts	0
Recorded Investment	0
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Commercial real estate [Member]
Troubled Debt Restructurings
Number of Contracts	0
Recorded Investment	0
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Residential real estate [Member]
Troubled Debt Restructurings
Number of Contracts	0
Recorded Investment	0
Troubled Debt Restructurings that Subsequently Defaulted [Member] | Consumer [Member]
Troubled Debt Restructurings
Number of Contracts	0
Recorded Investment	$ 0