Disclosures about Fair Value of Assets and Liabilities (Details 3) (USD $) In Thousands, unless otherwise specified							3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2013 Impaired loans [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Impaired loans [Member] Significant Unobservable Inputs (Level 3) [Member]	Mar. 31, 2013 Impaired loans [Member] Minimum [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Impaired loans [Member] Minimum [Member] Significant Unobservable Inputs (Level 3) [Member]	Mar. 31, 2013 Impaired loans [Member] Maximum [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Impaired loans [Member] Maximum [Member] Significant Unobservable Inputs (Level 3) [Member]	Mar. 31, 2013 Other real estate owned [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Other real estate owned [Member] Significant Unobservable Inputs (Level 3) [Member]	Mar. 31, 2013 Other real estate owned [Member] Minimum [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Other real estate owned [Member] Minimum [Member] Significant Unobservable Inputs (Level 3) [Member]	Mar. 31, 2013 Other real estate owned [Member] Maximum [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2012 Other real estate owned [Member] Maximum [Member] Significant Unobservable Inputs (Level 3) [Member]
Fair value Measurements of assets recognized
Fair Value, Measurement with unobservable inputs, Assets, Value			$ 2,364	$ 2,351	$ 7,936	$ 7,407						$ 1,165
Fair Value Assumptions, Weighted Average Volatility Rate							7.00%	7.00%	50.00%	50.00%				7.00%		16.20%