Fair Value Measurements, Fair Value Inputs, Quantitative Information (Details) (Fair Value, Inputs, Level 3 [Member])	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Appraisal Collateral - Appraisal Approach [Member] | Minimum [Member] | Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	5.00%	5.00%
Appraisal Collateral - Appraisal Approach [Member] | Minimum [Member] | Foreclosed Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	15.00%	15.00%
Appraisal Collateral - Appraisal Approach [Member] | Maximum [Member] | Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	30.00%	30.00%
Appraisal Collateral - Appraisal Approach [Member] | Maximum [Member] | Foreclosed Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	15.00%	15.00%
Appraisal Collateral - Appraisal Approach [Member] | Weighted Average [Member] | Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	21.00%	21.00%
Appraisal Collateral - Appraisal Approach [Member] | Weighted Average [Member] | Foreclosed Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	15.00%	15.00%
Appraisal Collateral - Cost to Sell Approach [Member] | Minimum [Member] | Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	6.00%	6.00%
Appraisal Collateral - Cost to Sell Approach [Member] | Minimum [Member] | Foreclosed Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	6.00%	6.00%
Appraisal Collateral - Cost to Sell Approach [Member] | Maximum [Member] | Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	50.00%	15.00%
Appraisal Collateral - Cost to Sell Approach [Member] | Maximum [Member] | Foreclosed Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	7.00%	7.00%
Appraisal Collateral - Cost to Sell Approach [Member] | Weighted Average [Member] | Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	12.00%	12.00%
Appraisal Collateral - Cost to Sell Approach [Member] | Weighted Average [Member] | Foreclosed Real Estate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value inputs, discount rate (in hundredths)	6.00%	6.00%