Disclosures about Fair Value of Assets and Liabilities (Details 3) (USD $) In Thousands, unless otherwise specified										9 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010	Sep. 30, 2012 Municipal Securities [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Impaired loans [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Other real estate owned [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Unrated Security Yield Adjustment [Member] Municipal Securities [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Liquidity yield adjustment [Member] Municipal Securities [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Discount to reflect realizable value [Member] Impaired loans [Member] Minimum [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Discount to reflect realizable value [Member] Impaired loans [Member] Maximum [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Discount to reflect realizable value [Member] Impaired loans [Member] Weighted Average [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Discount to reflect realizable value [Member] Other real estate owned [Member] Minimum [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Discount to reflect realizable value [Member] Other real estate owned [Member] Maximum [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Discount to reflect realizable value [Member] Other real estate owned [Member] Weighted Average [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Extension risk yield adjustment [Member] Municipal Securities [Member] Significant Unobservable Inputs (Level 3) [Member]
Fair value measurement of assets recognized
Fair Value, Measurement with unobservable inputs, Assets, Value	$ 2,350	$ 2,362	$ 2,351	$ 2,399			$ 2,350	$ 15,824	$ 233
Fair Value Assumptions, Weighted Average Volatility Rate										2.00%	2.00%	0.10%	46.50%	8.70%	9.10%	9.10%	9.10%	1.00%