Allowance for Credit Losses - Loan Portfolio by Risk Rating (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment
Loans	$ 415,277	$ 428,159
Pass
Financing Receivable, Recorded Investment
Loans	369,002	373,388
Special Mention
Financing Receivable, Recorded Investment
Loans	12,856	17,971
Substandard
Financing Receivable, Recorded Investment
Loans	33,419	36,800
Doubtful
Financing Receivable, Recorded Investment
Loans	0	0
Commercial
Financing Receivable, Recorded Investment
Loans	119,429	108,047
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment
Loans	75,786	78,089
Commercial | Agricultural land and production
Financing Receivable, Recorded Investment
Loans	43,643	29,958
Commercial | Pass | Commercial and industrial
Financing Receivable, Recorded Investment
Loans	68,088	70,093
Commercial | Pass | Agricultural land and production
Financing Receivable, Recorded Investment
Loans	43,643	29,958
Commercial | Special Mention | Commercial and industrial
Financing Receivable, Recorded Investment
Loans	819	2,595
Commercial | Special Mention | Agricultural land and production
Financing Receivable, Recorded Investment
Loans	0	0
Commercial | Substandard | Commercial and industrial
Financing Receivable, Recorded Investment
Loans	6,879	5,401
Commercial | Substandard | Agricultural land and production
Financing Receivable, Recorded Investment
Loans	0	0
Commercial | Doubtful | Commercial and industrial
Financing Receivable, Recorded Investment
Loans	0	0
Commercial | Doubtful | Agricultural land and production
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment
Financing Receivable, Recorded Investment
Loans	242,509	259,241
Real Estate Portfolio Segment | Owner occupied
Financing Receivable, Recorded Investment
Loans	109,336	113,183
Real Estate Portfolio Segment | Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	32,209	33,047
Real Estate Portfolio Segment | Commercial real estate
Financing Receivable, Recorded Investment
Loans	54,578	62,523
Real Estate Portfolio Segment | Agricultural real estate
Financing Receivable, Recorded Investment
Loans	38,160	42,596
Real Estate Portfolio Segment | Other real estate
Financing Receivable, Recorded Investment
Loans	8,226	7,892
Real Estate Portfolio Segment | Pass | Owner occupied
Financing Receivable, Recorded Investment
Loans	101,454	105,308
Real Estate Portfolio Segment | Pass | Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	16,798	15,717
Real Estate Portfolio Segment | Pass | Commercial real estate
Financing Receivable, Recorded Investment
Loans	44,156	47,323
Real Estate Portfolio Segment | Pass | Agricultural real estate
Financing Receivable, Recorded Investment
Loans	36,254	40,808
Real Estate Portfolio Segment | Pass | Other real estate
Financing Receivable, Recorded Investment
Loans	8,226	7,672
Real Estate Portfolio Segment | Special Mention | Owner occupied
Financing Receivable, Recorded Investment
Loans	2,211	3,125
Real Estate Portfolio Segment | Special Mention | Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	3,659	4,056
Real Estate Portfolio Segment | Special Mention | Commercial real estate
Financing Receivable, Recorded Investment
Loans	3,871	5,035
Real Estate Portfolio Segment | Special Mention | Agricultural real estate
Financing Receivable, Recorded Investment
Loans	1,906	1,788
Real Estate Portfolio Segment | Special Mention | Other real estate
Financing Receivable, Recorded Investment
Loans	0	220
Real Estate Portfolio Segment | Substandard | Owner occupied
Financing Receivable, Recorded Investment
Loans	5,671	4,750
Real Estate Portfolio Segment | Substandard | Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	11,752	13,274
Real Estate Portfolio Segment | Substandard | Commercial real estate
Financing Receivable, Recorded Investment
Loans	6,551	10,165
Real Estate Portfolio Segment | Substandard | Agricultural real estate
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment | Substandard | Other real estate
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment | Doubtful | Owner occupied
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment | Doubtful | Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment | Doubtful | Commercial real estate
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment | Doubtful | Agricultural real estate
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment | Doubtful | Other real estate
Financing Receivable, Recorded Investment
Loans	0	0
Consumer
Financing Receivable, Recorded Investment
Loans	53,339	60,871
Consumer | Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	44,761	51,106
Consumer | Consumer and installment
Financing Receivable, Recorded Investment
Loans	8,578	9,765
Consumer | Pass | Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	41,980	46,939
Consumer | Pass | Consumer and installment
Financing Receivable, Recorded Investment
Loans	8,403	9,570
Consumer | Special Mention | Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	299	1,047
Consumer | Special Mention | Consumer and installment
Financing Receivable, Recorded Investment
Loans	91	105
Consumer | Substandard | Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	2,482	3,120
Consumer | Substandard | Consumer and installment
Financing Receivable, Recorded Investment
Loans	84	90
Consumer | Doubtful | Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	0	0
Consumer | Doubtful | Consumer and installment
Financing Receivable, Recorded Investment
Loans	$ 0	$ 0