Goodwill and Core Deposit and Trust Relationship Intangibles (Changes in Core Deposit Intangible and Trust Relationship Intangible) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Core Deposit Intangible
Total
Beginning Balance	$ 14,444	$ 14,444
Activity	2,856
Ending Balance	17,300	14,444
Accumulated Amortization
Accumulated Amortization	(11,432)	(10,930)
Amortization	(582)	(502)
Accumulated Amortization	(12,014)	(11,432)
Net
Beginning Balance	3,012	3,514
Amortization	(582)	(502)
Activity	2,274
Ending Balance	5,286	3,012
Trust Relationship Intangible
Total
Beginning Balance	753	753
Activity
Ending Balance	753	753
Accumulated Amortization
Accumulated Amortization	(301)	(226)
Amortization	(75)	(75)
Accumulated Amortization	(376)	(301)
Net
Beginning Balance	452	527
Amortization	(75)	(75)
Ending Balance	$ 377	$ 452