Fair Value (Details 3) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Foreclosed assets, Fair Value	738,000	1,270,000
Non-recurring basis | Level 3
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans- held-for-investment, Fair Value	8,006,000	9,172,000
Foreclosed assets, Fair Value	738,000	1,270,000
Non-recurring basis | Level 3 | Land and construction
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Foreclosed assets, Fair Value	657,000	1,187,000
Non-recurring basis | Level 3 | Land and construction | Market Approach | Minimum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	1.00%	0.00%
Non-recurring basis | Level 3 | Land and construction | Market Approach | Maximum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	16.00%	23.00%
Non-recurring basis | Level 3 | Land and construction | Market Approach | Weighted average
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	7.00%	6.00%
Non-recurring basis | Level 3 | Commercial
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans- held-for-investment, Fair Value	2,982,000	3,645,000
Foreclosed assets, Fair Value	81,000	83,000
Non-recurring basis | Level 3 | Commercial | Market Approach | Minimum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	0.00%	0.00%
Non-recurring basis | Level 3 | Commercial | Market Approach | Maximum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	3.00%	4.00%
Non-recurring basis | Level 3 | Commercial | Market Approach | Weighted average
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	2.00%	1.00%
Non-recurring basis | Level 3 | Real estate | Commercial and residential
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans- held-for-investment, Fair Value	3,217,000	3,674,000
Non-recurring basis | Level 3 | Real estate | Commercial and residential | Market Approach | Minimum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	0.00%	0.00%
Non-recurring basis | Level 3 | Real estate | Commercial and residential | Market Approach | Maximum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	13.00%	13.00%
Non-recurring basis | Level 3 | Real estate | Commercial and residential | Market Approach | Weighted average
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	1.00%	1.00%
Non-recurring basis | Level 3 | Real estate | Land and construction
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans- held-for-investment, Fair Value	1,685,000	1,723,000
Non-recurring basis | Level 3 | Real estate | Land and construction | Market Approach | Minimum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	1.00%	1.00%
Non-recurring basis | Level 3 | Real estate | Land and construction | Market Approach | Maximum
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	4.00%	4.00%
Non-recurring basis | Level 3 | Real estate | Land and construction | Market Approach | Weighted average
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value on a non-recurring basis
Discount adjustment for differences between comparable sales (as a percent)	2.00%	2.00%