Allowance for Credit Losses - Loan Portfolio Aging (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	$ 776	$ 1,741
60-89 Days Past Due	149	74
Greater Than 90 Days Past Due	0	3,999
Total Past Due	925	5,814
Current	414,352	422,345
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	10,242	14,434
Loans	415,277	428,159
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans	119,429	108,047
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	57
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	236
Total Past Due	0	293
Current	75,786	77,796
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	0	267
Loans	75,786	78,089
Commercial | Agricultural land and production
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	0
Total Past Due	0	0
Current	43,643	29,958
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	0	0
Loans	43,643	29,958
Real Estate Portfolio Segment
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans	242,509	259,241
Real Estate Portfolio Segment | Owner occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	122
Total Past Due	0	122
Current	109,336	113,061
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	1,631	1,372
Loans	109,336	113,183
Real Estate Portfolio Segment | Real estate construction and other land loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	730	1,532
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	0
Total Past Due	730	1,532
Current	31,479	31,515
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	6,562	6,823
Loans	32,209	33,047
Real Estate Portfolio Segment | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	3,544
Total Past Due	0	3,544
Current	54,578	58,979
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	0	3,544
Loans	54,578	62,523
Real Estate Portfolio Segment | Agricultural real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	0
Total Past Due	0	0
Current	38,160	42,596
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	0	0
Loans	38,160	42,596
Real Estate Portfolio Segment | Other real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater Than 90 Days Past Due	0	0
Total Past Due	0	0
Current	8,226	7,892
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	0	0
Loans	8,226	7,892
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans	53,339	60,871
Consumer | Equity loans and lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	0	123
60-89 Days Past Due	78	0
Greater Than 90 Days Past Due	0	97
Total Past Due	78	220
Current	44,683	50,886
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	1,978	2,354
Loans	44,761	51,106
Consumer | Consumer and installment
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	46	29
60-89 Days Past Due	71	74
Greater Than 90 Days Past Due	0	0
Total Past Due	117	103
Current	8,461	9,662
Recorded Investment Greater Than 90 Days Accruing	0	0
Non-accrual	71	74
Loans	$ 8,578	$ 9,765