Loans and Allowance for Loan Losses (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) alternative	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Loan and Lease Losses	$ 143,000	$ 128,000	$ 408,000	$ 451,000
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	143,000	128,000	408,000	451,000	$ 629,000
Gross loans						$ 1,056,657,000	$ 1,060,685,000
Less [Abstract]
Net deferred loan fees, premiums and discounts						130,000	237,000
Allowance for loan losses	14,106,000	13,603,000	13,682,000	13,249,000	13,249,000	13,931,000	13,682,000	$ 13,681,000
Net loans						1,042,596,000	1,046,766,000
Loans held for sale						2,576,000	1,958,000
Impaired Loans [Abstract]
Minimum value of loans individually measured for impairment			$ 250,000
Number of alternatives for measuring impaired loans receivable | alternative			3
Adversely Classified Loans [Abstract]
Minimum balance of adversely classified loan in which a detailed analysis is performed			$ 250,000
Non-classified and Watch Loans [Abstract]
Time period used a a base for loss estimations
Allowance for Loan Losses [Abstract]
Balance, beginning of period	14,106,000	13,603,000	$ 13,682,000	13,249,000	13,249,000
Losses charged off	(381,000)	(102,000)	(471,000)	(182,000)	(537,000)
Recoveries	63,000	52,000	312,000	163,000	341,000
Balance, end of period	13,931,000	13,681,000	$ 13,931,000	13,681,000	13,682,000
Ending Balance [Abstract]
Individually evaluated for impairment						537,000	263,000	322,000
Collectively evaluated for impairment						13,394,000	13,419,000	13,359,000
Loans [Abstract]
Ending balance						1,059,103,000	1,062,406,000	1,022,251,000
Ending Balance [Abstract]
Individually evaluated for impairment						1,766,000	3,301,000	3,648,000
Collectively evaluated for impairment						1,057,337,000	1,059,105,000	1,018,603,000
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						27,420,000	21,627,000
Agricultural real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						112,270,000	110,158,000
1-4 Family residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						170,697,000	179,886,000
Ending Balance [Abstract]
Period When Loans are Charged-down
Multifamily residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						52,422,000	53,129,000
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						372,213,000	380,173,000
Loans Receivable Additional Information [Abstract]
Debt coverage ratio			1.20x
Amortization period of loans
Commercial real estate | Minimum [Member]
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			65.00%
Commercial real estate | Maximum [Member]
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			80.00%
Loans secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						735,022,000	744,973,000
Agricultural loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						59,641,000	68,225,000
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						238,981,000	223,633,000
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			80.00%
Amortization period of loans
Loans Receivable, Time Period
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	258,000	27,000	$ 262,000	36,000	167,000
Gross loans						14,560,000	15,118,000
Less [Abstract]
Allowance for loan losses	386,000	372,000	386,000	377,000	377,000	382,000	386,000	368,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	386,000	372,000	386,000	377,000	377,000
Losses charged off	(304,000)	(60,000)	(360,000)	(105,000)	(311,000)
Recoveries	42,000	29,000	94,000	60,000	153,000
Balance, end of period	382,000	368,000	382,000	368,000	386,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						382,000	386,000	368,000
Loans [Abstract]
Ending balance						15,451,000	15,102,000	14,304,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						15,451,000	15,102,000	14,304,000
All other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						8,453,000	8,736,000
Agricultural and Farm Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						172,000,000	178,500,000
Less [Abstract]
Decrease in loans receivable			$ (6,500,000)
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			65.00%
Amortization period of loans
Loans Receivable, Time Period
Other Grain Farming [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						144,700,000	155,100,000
Less [Abstract]
Decrease in loans receivable			$ (10,400,000)
Motels and Hotels Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						55,800,000
Non-residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						105,200,000
Residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						62,500,000
Unsecured Open-end Loans [Member]
Ending Balance [Abstract]
Period When Loans are Charged-down
Other Secured Loans [Member]
Ending Balance [Abstract]
Period When Loans are Charged-down
Commercial/ Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	(123,000)	200,000	$ 235,000	75,000	192,000
Less [Abstract]
Allowance for loan losses	11,459,000	10,581,000	10,914,000	10,646,000	10,646,000	11,294,000	10,914,000	10,771,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	11,459,000	10,581,000	10,914,000	10,646,000	10,646,000
Losses charged off	(62,000)	(28,000)	(71,000)	(32,000)	(86,000)
Recoveries	20,000	18,000	216,000	82,000	162,000
Balance, end of period	11,294,000	10,771,000	11,294,000	10,771,000	10,914,000
Ending Balance [Abstract]
Individually evaluated for impairment						537,000	263,000	322,000
Collectively evaluated for impairment						10,757,000	10,651,000	10,449,000
Loans [Abstract]
Ending balance						696,596,000	684,552,000	657,352,000
Ending Balance [Abstract]
Individually evaluated for impairment						1,766,000	3,301,000	3,648,000
Collectively evaluated for impairment						694,830,000	681,251,000	653,704,000
Agricultural/ Agricultural Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	20,000	21,000	(49,000)	(10,000)	825,000
Less [Abstract]
Allowance for loan losses	1,291,000	503,000	1,360,000	533,000	533,000	1,312,000	1,360,000	524,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	1,291,000	503,000	1,360,000	533,000	533,000
Losses charged off	0	0	0	0	0
Recoveries	1,000	0	1,000	1,000	2,000
Balance, end of period	1,312,000	524,000	1,312,000	524,000	1,360,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						1,312,000	1,360,000	524,000
Loans [Abstract]
Ending balance						171,376,000	178,091,000	164,841,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						171,376,000	178,091,000	164,841,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	(7,000)	6,000	(20,000)	11,000	135,000
Less [Abstract]
Allowance for loan losses	753,000	760,000	$ 790,000	771,000	771,000	731,000	790,000	757,000
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			80.00%
Amortization period of loans
Balloon period
Allowance for Loan Losses [Abstract]
Balance, beginning of period	753,000	760,000	$ 790,000	771,000	771,000
Losses charged off	(15,000)	(14,000)	(40,000)	(45,000)	(140,000)
Recoveries	0	5,000	1,000	20,000	24,000
Balance, end of period	731,000	757,000	731,000	757,000	790,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						731,000	790,000	757,000
Loans [Abstract]
Ending balance						175,680,000	184,661,000	185,754,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						175,680,000	184,661,000	185,754,000
Unallocated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	(5,000)	(126,000)	(20,000)	339,000	(690,000)
Less [Abstract]
Allowance for loan losses	217,000	1,387,000	232,000	922,000	922,000	212,000	232,000	1,261,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	217,000	1,387,000	232,000	922,000	922,000
Losses charged off	0	0	0	0	0
Recoveries	0	0	0	0	0
Balance, end of period	$ 212,000	$ 1,261,000	$ 212,000	$ 1,261,000	$ 232,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						212,000	232,000	1,261,000
Loans [Abstract]
Ending balance						0	0	0
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						$ 0	$ 0	$ 0