Loan and Lease Receivables, Impaired Loans and Leases and Allowance for Loan and Lease Losses (Narrative Disclosures) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Receivables [Abstract]
Loans And Leases Transferred To Third Parties Total Principal Amount	$ 8,800,000	$ 8,600,000	$ 34,700,000	$ 10,100,000
Total loans and leases transferred to third parties that qualify for sale accounting	8,800,000	8,600,000	34,700,000	10,100,000
Total amount of outstanding loans transferred to third parties as loan participations	43,100,000		43,100,000		49,200,000
Total amount of loan participations remaining on the Corporation’s balance sheet	65,200,000		65,200,000		74,600,000
Loans in the participation sold portfolio, considered impaired	3,400,000		3,400,000		3,400,000
Charge-offs to specific credits within the retained portion of the participation sold portfolio	2,700,000		2,700,000
Loans and leases identified as Substandard	30,200,000		30,200,000		42,600,000
Loans and leases identified as Special Mention					0
Loans and leases identified as Doubtful	0		0		0
Loans and leases identified as Loss	0		0		0
Impaired troubled debt restructurings	11,400,000		11,400,000		13,300,000
Unfunded commitments, troubled debt restructurings	0		0
Loans and Leases Receivable, Difference between Recorded Investment and Unpaid Principal Balance	8,100,000		8,100,000		7,900,000
Performing troubled debt restructurings	$ 536,000		$ 536,000		$ 111,000