Acquisition Activity (Schedule Of Components Of Estimated Fair Value Of Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Core Deposit Intangible [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 8.2
Estimated Useful Lives (Years)	10
Trust Customer Relationship Intangible [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 2.3
Estimated Useful Lives (Years)	12

The useful life of all finite-lived intangible assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 12, 13, 14

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 35

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6904245&loc=d3e15372-109273

Name:	us-gaap_FiniteLivedIntangibleAssetsUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration