Fair Values of Assets and Liabilities (Quantitative Information about Level 3 Fair Value Measurements) (Details) (Level 3 [Member], Nonrecurring [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Discounted Appraisal [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Impaired loans, net	12,968	13,575
Other real estate owned	33,790	48,480
Discounted Cash Flows [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Mortgage servicing rights	1,028	726
Impaired loans [Member] | Discounted Appraisal [Member] | Lower range [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Collateral discounts	6.00%	6.00%
Impaired loans [Member] | Discounted Appraisal [Member] | Upper range [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Collateral discounts	40.00%	40.00%
Other real estate owned [Member] | Discounted Appraisal [Member] | Lower range [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Collateral discounts	6.00%	6.00%
Other real estate owned [Member] | Discounted Appraisal [Member] | Upper range [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Collateral discounts	40.00%	40.00%
Mortgage servicing rights [Member] | Discounted Cash Flows [Member] | Lower range [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment rate	10.00%	10.00%
Discount rate	4.00%	4.00%
Mortgage servicing rights [Member] | Discounted Cash Flows [Member] | Upper range [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Prepayment rate	30.00%	30.00%
Discount rate	12.00%	12.00%
Continuing operations [Member]
Fair Value Inputs, Quantitative Information [Line Items]
Impaired loans, net	12,968	13,575
Other real estate owned	33,790	48,480