Loans and Leases and the Allowance for Loan and Lease Losses (Details 6) (USD $)	12 Months Ended
	Dec. 31, 2011 M contract	Dec. 31, 2010
Loans and Leases and the Allowance for Loan and Lease Losses
Loans modified in a TDR	$ 38,800,000	$ 32,700,000
Lease financing modifications, forbearance period (in months)	3
Loans Modified as a TDR
Number of Contracts	320
Recorded Investment (as of period end)	16,173,000
Increase in Allowance (as of period end)	1,809,000
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Number of Contracts	15
Recorded Investment (as of period end)	1,400,000
Minimum
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Default period past due following modification of loans in TDR (in days)	60
Commercial
Loans Modified as a TDR
Number of Contracts	11
Recorded Investment (as of period end)	5,530,000
Increase in Allowance (as of period end)	801,000
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Number of Contracts	2
Recorded Investment (as of period end)	957,000
Commercial and Industrial
Loans Modified as a TDR
Number of Contracts	7
Recorded Investment (as of period end)	4,281,000
Increase in Allowance (as of period end)	782,000
Commercial Mortgage
Loans Modified as a TDR
Number of Contracts	4
Recorded Investment (as of period end)	1,249,000
Increase in Allowance (as of period end)	19,000
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Number of Contracts	2
Recorded Investment (as of period end)	957,000
Short-term forbearance period (in months)	6
Consumer
Loans Modified as a TDR
Number of Contracts	309
Recorded Investment (as of period end)	10,643,000
Increase in Allowance (as of period end)	1,008,000
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Number of Contracts	13
Recorded Investment (as of period end)	443,000
Residential Mortgage
Information related to loans modified as a TDR
Period of loans modified in TDR (in years)	2
Loans Modified as a TDR
Number of Contracts	17
Recorded Investment (as of period end)	7,384,000
Increase in Allowance (as of period end)	964,000
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Number of Contracts	1
Recorded Investment (as of period end)	293,000
Automobile
Loans Modified as a TDR
Number of Contracts	289
Recorded Investment (as of period end)	2,946,000
Increase in Allowance (as of period end)	36,000
TDRs that Defaulted During the Period, Within Twelve Months of their Modification Date
Number of Contracts	12
Recorded Investment (as of period end)	150,000
Other Consumer
Loans Modified as a TDR
Number of Contracts	3
Recorded Investment (as of period end)	313,000
Increase in Allowance (as of period end)	$ 8,000
Land Loans | Minimum
Information related to loans modified as a TDR
Period for the balloon payment extension (in years)	1
Land Loans | Maximum
Information related to loans modified as a TDR
Period for the balloon payment extension (in years)	3