Loans And Allowance For Credit Losses (Schedule Of Investment Of Accruing And Nonaccruing Loans Modified As Troubled Debt Restructurings) (Details) (USD $)	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	$ 3,644,000	$ 22,559,000
Loans modified as TDRs	276,200,000
Accruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default		35,000
Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	3,644,000	22,524,000
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,563,000	2,176,000
Commercial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default		35,000
Commercial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,563,000	2,141,000
Commercial [Member] | Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	249,000	1,735,000
Commercial [Member] | Commercial And Industrial [Member] | Accruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default		35,000
Commercial [Member] | Commercial And Industrial [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	249,000	1,700,000
Commercial [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,314,000	441,000
Commercial [Member] | Owner Occupied [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,314,000	441,000
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,555,000	17,638,000
Commercial Real Estate [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,555,000	17,638,000
Commercial Real Estate [Member] | Construction And Land Development [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default		11,667,000
Commercial Real Estate [Member] | Construction And Land Development [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default		11,667,000
Commercial Real Estate [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,555,000	5,971,000
Commercial Real Estate [Member] | Term [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	1,555,000	5,971,000
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	526,000	2,745,000
Consumer [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	526,000	2,745,000
Consumer [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	526,000	2,745,000
Consumer [Member] | 1-4 Family Residential [Member] | Nonaccruing [Member]
Financing Receivable, Modifications [Line Items]
Recorded investment modified as TDRs previous to payment default	$ 526,000	$ 2,745,000