Allowance for Credit Losses - Loan Portfolio by Risk Rating (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment
Loans	$ 515,469	$ 395,771
Pass
Financing Receivable, Recorded Investment
Loans	469,263	354,169
Special Mention
Financing Receivable, Recorded Investment
Loans	18,588	11,836
Substandard
Financing Receivable, Recorded Investment
Loans	27,618	29,766
Doubtful
Financing Receivable, Recorded Investment
Loans	0	0
Commercial
Financing Receivable, Recorded Investment
Loans	133,661	104,555
Commercial \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	89,991	77,956
Commercial \| Agricultural land and production
Financing Receivable, Recorded Investment
Loans	43,670	26,599
Commercial \| Pass \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	83,958	71,125
Commercial \| Pass \| Agricultural land and production
Financing Receivable, Recorded Investment
Loans	43,670	26,599
Commercial \| Special Mention \| Commercial and industrial
Financing Receivable, Recorded Investment
Loans	2,626	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	3,407	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	319,738	237,938
Real Estate Portfolio Segment \| Owner occupied
Financing Receivable, Recorded Investment
Loans	155,171	114,444
Real Estate Portfolio Segment \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	35,327	33,199
Real Estate Portfolio Segment \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	85,457	53,797
Real Estate Portfolio Segment \| Agricultural real estate
Financing Receivable, Recorded Investment
Loans	39,857	28,400
Real Estate Portfolio Segment \| Other real estate
Financing Receivable, Recorded Investment
Loans	3,926	8,098
Real Estate Portfolio Segment \| Pass \| Owner occupied
Financing Receivable, Recorded Investment
Loans	142,344	107,281
Real Estate Portfolio Segment \| Pass \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	25,642	18,517
Real Estate Portfolio Segment \| Pass \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	76,661	44,880
Real Estate Portfolio Segment \| Pass \| Agricultural real estate
Financing Receivable, Recorded Investment
Loans	37,856	26,883
Real Estate Portfolio Segment \| Pass \| Other real estate
Financing Receivable, Recorded Investment
Loans	3,926	8,098
Real Estate Portfolio Segment \| Special Mention \| Owner occupied
Financing Receivable, Recorded Investment
Loans	5,294	1,831
Real Estate Portfolio Segment \| Special Mention \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	2,405	3,377
Real Estate Portfolio Segment \| Special Mention \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	3,745	3,952
Real Estate Portfolio Segment \| Special Mention \| Agricultural real estate
Financing Receivable, Recorded Investment
Loans	2,001	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	7,533	5,332
Real Estate Portfolio Segment \| Substandard \| Real estate construction and other land loans
Financing Receivable, Recorded Investment
Loans	7,280	11,305
Real Estate Portfolio Segment \| Substandard \| Commercial real estate
Financing Receivable, Recorded Investment
Loans	5,051	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	62,070	53,278
Consumer \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	51,293	42,932
Consumer \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	10,777	10,346
Consumer \| Pass \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	44,508	40,527
Consumer \| Pass \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	10,698	10,259
Consumer \| Special Mention \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	2,465	258
Consumer \| Special Mention \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	52	77
Consumer \| Substandard \| Equity loans and lines of credit
Financing Receivable, Recorded Investment
Loans	4,320	2,147
Consumer \| Substandard \| Consumer and installment
Financing Receivable, Recorded Investment
Loans	27	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