Fair Value Accounting and Measurement Fair Value, quantitative inputs to Level 3 measurements (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Impaired loans	$ 10,599	$ 17,755
Other Real Estate Owned, Fair Value Disclosure	2,663	2,442
Other Personal Property Owned, Fair Value Disclosure	210
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Impaired loans	10,599	17,755
Other Real Estate Owned, Fair Value Disclosure	2,663	2,442
Other Personal Property Owned, Fair Value Disclosure	210
Fair Value, Inputs, Level 3 [Member] | Other Collateral [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Impaired loans	500
Fair Value, Inputs, Level 3 [Member] | Real Estate Collateral [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Impaired loans	10,099
Noncovered Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Other Real Estate Owned, Fair Value Disclosure	10,970
Other Personal Property Owned, Fair Value Disclosure	210
Covered Loans [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Other Real Estate Owned, Fair Value Disclosure	$ 2,663