Fair Market Value of Financial Assets and Liabilities, Quantitative Information about Level 3 Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Mortgage Servicing Rights [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 3,222	$ 2,364
Mortgage Servicing Rights [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Constant prepayment rate (in hundredths)	6.10%	8.50%
Probability of default (in hundredths)	0.52%	1.02%
Mortgage Servicing Rights [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Constant prepayment rate (in hundredths)	26.00%	25.00%
Probability of default (in hundredths)	5.77%	4.81%
Mortgage Servicing Rights [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Constant prepayment rate (in hundredths)	12.30%	16.30%
Probability of default (in hundredths)	2.61%	2.65%
Discount rate (in hundredths)	10.50%	10.50%
Impaired Loans (Collateral Dependent) [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	5,419	5,465
Impaired Loans (Collateral Dependent) [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Marketability discount (in hundredths)	5.00%	5.00%
Impaired Loans (Collateral Dependent) [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Marketability discount (in hundredths)	10.00%	10.00%
Impaired Loans (Collateral Dependent) [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Marketability discount (in hundredths)	7.00%	7.00%
Other Real Estate/Asset Owned [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 9,587	$ 13,892
Other Real Estate/Asset Owned [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Comparability adjustments (in hundredths)	5.00%	5.00%
Other Real Estate/Asset Owned [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Comparability adjustments (in hundredths)	57.00%	35.00%
Other Real Estate/Asset Owned [Member] | Weighted Average [Member]
Fair Value Inputs [Abstract]
Comparability adjustments (in hundredths)	10.00%	13.00%