Business Combinations Estimated Fair Values Of Assets Acquired And Liabilities Assumed (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Sep. 10, 2010 First Bank [Member]	Sep. 10, 2010 Acquired Book Value [Member] First Bank [Member]	Sep. 10, 2010 Fair Value Adjustments [Member] First Bank [Member]
Assets
Cash			$ 180,074	$ 180,074	$ 0
Loans			133,117	135,219	(2,102)
Premises and equipment			12,951	5,266	7,685
Goodwill	25,753	25,753	8,390	0	8,390
Core deposit intangible			3,050	0	3,050
Other assets			488	488	0
Total assets acquired			338,070	321,047	17,023
Liabilities
Deposits			337,429	336,016	1,413
Securities sold under agreements to repurchase			126	126	0
Other liabilities			515	515	0
Total liabilities assumed			$ 338,070	$ 336,657	$ 1,413