Loans and Allowance for Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 911,597	$ 859,732
Net deferred loan fees, premiums and discounts	(744)	(704)
Allowance for loan losses	11,776	11,120	10,393	9,462
Net loans	899,077	847,908
Loans held for sale	212	1,046
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	31,341	23,136
Farm loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	86,256	72,586
1-4 Family residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	186,205	180,738
Multifamily residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	44,863	19,847
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	317,321	321,908
Debt coverage ratio	1.20x
Amortization period of loans	twenty years
Commercial real estate | Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan To Value Ratio	65.00%
Commercial real estate | Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan To Value Ratio	80.00%
Loans secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	665,986	618,215
Agricultural loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	60,948	63,182
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	160,193	150,631
Loan To Value Ratio	80.00%
Amortization period of loans	seven years
Loans Receivable, Time Period	one year
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	16,264	16,274
Allowance for loan losses	403	378	392	410
All other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	8,206	11,430
Agricultural and Farm Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	147,200	135,800
Increase (Decrease) in Accounts and Notes Receivable	11,400
Loan To Value Ratio	65.00%
Amortization period of loans	twenty five years
Loans Receivable, Time Period	one year
Other Grain Farming [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	124,400	120,061
Increase (Decrease) in Accounts and Notes Receivable	4,300
Motels and Hotels Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	45,783
Non-residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	89,940
Residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	59,848
Commercial/Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	9,301	8,791	8,307	7,428
Agriculture/Agricultural Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	558	546	404	315
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	726	636	440	488
Loan To Value Ratio	80.00%
Amortization period of loans	twenty five years
Balloon period	five years
Unallocated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses	$ 788	$ 769	$ 850	$ 821