Fair Value Measurements (Quantitative Information About Level 3 Assets Measured at Fair Value on a Nonrecurring Basis) (Details) (Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
Fair Value Inputs Assets Quantitative Information [Line Items]
Collateral dependent impaired loans	8,937		9,550
Property acquired through foreclosure or repossession	1,170		1,073
Level 3 [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Collateral dependent impaired loans	8,937		9,550
Property acquired through foreclosure or repossession	1,170		1,073
Appraisals Of Collateral [Member] | Range of Inputs: Minimum [Member] | Level 3 [Member] | Collateral Dependent Impaired Loans [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount For Costs To Sell	1.00%		0.00%
Appraisal Adjustments	0.00%	[1]	0.00%	[1]
Appraisals Of Collateral [Member] | Range of Inputs: Minimum [Member] | Level 3 [Member] | Property Acquired Through Foreclosure Or Repossession [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount For Costs To Sell	0.00%		0.00%
Appraisal Adjustments	0.00%	[1]	15.00%	[1]
Appraisals Of Collateral [Member] | Range of Inputs: Maximum [Member] | Level 3 [Member] | Collateral Dependent Impaired Loans [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount For Costs To Sell	50.00%		50.00%
Appraisal Adjustments	25.00%	[1]	27.00%	[1]
Appraisals Of Collateral [Member] | Range of Inputs: Maximum [Member] | Level 3 [Member] | Property Acquired Through Foreclosure Or Repossession [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount For Costs To Sell	10.00%		10.00%
Appraisal Adjustments	34.00%	[1]	34.00%	[1]
Appraisals Of Collateral [Member] | Weighted Average [Member] | Level 3 [Member] | Collateral Dependent Impaired Loans [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount For Costs To Sell	9.00%		11.00%
Appraisal Adjustments	12.00%	[1]	18.00%	[1]
Appraisals Of Collateral [Member] | Weighted Average [Member] | Level 3 [Member] | Property Acquired Through Foreclosure Or Repossession [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Discount For Costs To Sell	2.00%		5.00%
Appraisal Adjustments	9.00%	[1]	21.00%	[1]

[1] Management may adjust appraisal values to reflect market value declines or other discounts resulting from its knowledge of the property.