Loans And Allowance For Credit Losses (Summary Of Net Financial Impact On Interest Income Due To Interest Rate Modifications Below Market For Accruing TDR Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2012		Jun. 30, 2012		Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	$ (6,164)	[1]	$ (12,313)	[1]	$ (19,630)	[1]
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(337)		(728)		(1,696)
Commercial [Member] | Commercial And Industrial [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(8)		(23)		(46)
Commercial [Member] | Owner Occupied [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(329)		(705)		(1,650)
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(1,709)		(3,495)		(7,340)
Commercial Real Estate [Member] | Construction And Land Development [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(236)		(469)		(244)
Commercial Real Estate [Member] | Term [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(1,473)		(3,026)		(7,096)
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(4,118)		(8,090)		(10,594)
Consumer [Member] | Home Equity Credit Line [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(19)		(34)		0
Consumer [Member] | 1-4 Family Residential [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	(3,992)		(7,841)		(10,188)
Consumer [Member] | Construction And Other Consumer Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Net financial impact on interest income	$ (107)		$ (215)		$ (406)

[1] Calculated based on the difference between the modified rate and the premodified rate applied to the recorded investment.