Allowance for Credit Losses - Loan Portfolio by Risk Rating (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment
Loans	$ 405,235	$ 395,771
Pass
Financing Receivable, Recorded Investment
Loans	365,147	354,169
Special Mention
Financing Receivable, Recorded Investment
Loans	13,701	11,836
Substandard
Financing Receivable, Recorded Investment
Loans	26,387	29,766
Doubtful
Financing Receivable, Recorded Investment
Loans	0	0
Commercial
Financing Receivable, Recorded Investment
Loans	115,882	104,555
Commercial \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	77,126	77,956
Commercial \| Agricultural land and production
Financing Receivable, Recorded Investment
Loans	38,756	26,599
Commercial \| Pass \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	73,891	71,125
Commercial \| Pass \| Agricultural land and production
Financing Receivable, Recorded Investment
Loans	38,756	26,599
Commercial \| Special Mention \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	431	824
Commercial \| Special Mention \| Agricultural land and production
Financing Receivable, Recorded Investment
Loans	0	0
Commercial \| Substandard \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	2,804	6,007
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	243,230	237,938
Real Estate Portfolio Segment \| Owner occupied
Financing Receivable, Recorded Investment
Loans	112,114	114,444
Real Estate Portfolio Segment \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	33,697	33,199
Real Estate Portfolio Segment \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	60,782	53,797
Real Estate Portfolio Segment \| Agricultural real estate
Financing Receivable, Recorded Investment
Loans	31,607	28,400
Real Estate Portfolio Segment \| Other real estate
Financing Receivable, Recorded Investment
Loans	5,030	8,098
Real Estate Portfolio Segment \| Pass \| Owner occupied
Financing Receivable, Recorded Investment
Loans	104,245	107,281
Real Estate Portfolio Segment \| Pass \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	20,130	18,517
Real Estate Portfolio Segment \| Pass \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	51,955	44,880
Real Estate Portfolio Segment \| Pass \| Agricultural real estate
Financing Receivable, Recorded Investment
Loans	29,594	26,883
Real Estate Portfolio Segment \| Pass \| Other real estate
Financing Receivable, Recorded Investment
Loans	5,030	8,098
Real Estate Portfolio Segment \| Special Mention \| Owner occupied
Financing Receivable, Recorded Investment
Loans	2,689	1,831
Real Estate Portfolio Segment \| Special Mention \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	2,429	3,377
Real Estate Portfolio Segment \| Special Mention \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	3,769	3,952
Real Estate Portfolio Segment \| Special Mention \| Agricultural real estate
Financing Receivable, Recorded Investment
Loans	2,013	1,517
Real Estate Portfolio Segment \| Special Mention \| Other real estate
Financing Receivable, Recorded Investment
Loans	0	0
Real Estate Portfolio Segment \| Substandard \| Owner occupied
Financing Receivable, Recorded Investment
Loans	5,180	5,332
Real Estate Portfolio Segment \| Substandard \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	11,138	11,305
Real Estate Portfolio Segment \| Substandard \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	5,058	4,965
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	46,123	53,278
Consumer \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	39,448	42,932
Consumer \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	6,675	10,346
Consumer \| Pass \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	34,939	40,527
Consumer \| Pass \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	6,607	10,259
Consumer \| Special Mention \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	2,310	258
Consumer \| Special Mention \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	60	77
Consumer \| Substandard \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	2,199	2,147
Consumer \| Substandard \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	8	10
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