Loans and Allowance for Loan Losses (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) alternative	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for Loan and Lease Losses	$ 481,000	$ 44,000	$ 889,000	$ 495,000
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	481,000	44,000	889,000	495,000	$ 629,000
Gross loans						$ 1,238,853,000	$ 1,060,685,000
Less [Abstract]
Net deferred loan fees, premiums and discounts						3,450,000	237,000
Allowance for loan losses	13,931,000	13,681,000	13,682,000	13,249,000	13,249,000	14,228,000	13,682,000	$ 13,705,000
Net loans						1,221,175,000	1,046,766,000
Loans held for sale						1,346,000	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			five-year
Allowance for Loan Losses [Abstract]
Balance, beginning of period	13,931,000	13,681,000	$ 13,682,000	13,249,000	13,249,000
Losses charged off	(270,000)	(133,000)	(741,000)	(315,000)	(537,000)
Recoveries	86,000	113,000	398,000	276,000	341,000
Balance, end of period	14,228,000	13,705,000	$ 14,228,000	13,705,000	13,682,000
Ending Balance [Abstract]
Individually evaluated for impairment						342,000	263,000	307,000
Collectively evaluated for impairment						13,886,000	13,419,000	13,398,000
Loans [Abstract]
Ending balance						1,236,749,000	1,062,406,000	1,041,008,000
Ending Balance [Abstract]
Individually evaluated for impairment						1,883,000	3,301,000	3,698,000
Collectively evaluated for impairment						1,234,866,000	1,059,105,000	1,037,310,000
Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						33,426,000	21,627,000
Agricultural real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						120,431,000	110,158,000
1-4 Family residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						234,273,000	179,886,000
Ending Balance [Abstract]
Period When Loans are Charged-down			180 days
Multifamily residential properties
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						54,961,000	53,129,000
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						378,665,000	380,173,000
Loans Receivable Additional Information [Abstract]
Debt coverage ratio			1.20x
Amortization period of loans			twenty years
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						821,756,000	744,973,000
Agricultural loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						65,520,000	68,225,000
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						296,334,000	223,633,000
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			80.00%
Amortization period of loans			seven years
Loans Receivable, Time Period			one year
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	305,000	58,000	$ 567,000	94,000	167,000
Gross loans						44,041,000	15,118,000
Less [Abstract]
Allowance for loan losses	382,000	368,000	386,000	377,000	377,000	654,000	386,000	387,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	382,000	368,000	386,000	377,000	377,000
Losses charged off	(72,000)	(81,000)	(432,000)	(186,000)	(311,000)
Recoveries	39,000	42,000	133,000	102,000	153,000
Balance, end of period	654,000	387,000	654,000	387,000	386,000
Ending Balance [Abstract]
Individually evaluated for impairment						194,000	0	0
Collectively evaluated for impairment						460,000	386,000	387,000
Loans [Abstract]
Ending balance						44,325,000	15,102,000	15,522,000
Ending Balance [Abstract]
Individually evaluated for impairment						224,000	0	0
Collectively evaluated for impairment						44,101,000	15,102,000	15,522,000
All other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						11,202,000	8,736,000
Agricultural and Farm Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						186,000,000	178,500,000
Less [Abstract]
Decrease in loans receivable			$ 7,500,000
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			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						154,800,000	155,100,000
Less [Abstract]
Decrease in loans receivable			$ (300,000)
Motels and Hotels Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						60,500,000
Non-residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						106,900,000
Residential Buildings [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans						68,000,000
Unsecured Open-end Loans [Member]
Ending Balance [Abstract]
Period When Loans are Charged-down			180 days
Other Secured Loans [Member]
Ending Balance [Abstract]
Period When Loans are Charged-down			120 days
Commercial/ Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	84,000	(267,000)	$ 319,000	(192,000)	192,000
Less [Abstract]
Allowance for loan losses	11,294,000	10,771,000	10,914,000	10,646,000	10,646,000	11,251,000	10,914,000	10,548,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	11,294,000	10,771,000	10,914,000	10,646,000	10,646,000
Losses charged off	(174,000)	(22,000)	(245,000)	(54,000)	(86,000)
Recoveries	47,000	66,000	263,000	148,000	162,000
Balance, end of period	11,251,000	10,548,000	11,251,000	10,548,000	10,914,000
Ending Balance [Abstract]
Individually evaluated for impairment						148,000	263,000	293,000
Collectively evaluated for impairment						11,103,000	10,651,000	10,255,000
Loans [Abstract]
Ending balance						772,388,000	684,552,000	667,656,000
Ending Balance [Abstract]
Individually evaluated for impairment						1,248,000	3,301,000	3,473,000
Collectively evaluated for impairment						771,140,000	681,251,000	664,183,000
Agricultural/ Agricultural Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	84,000	775,000	35,000	765,000	825,000
Less [Abstract]
Allowance for loan losses	1,312,000	524,000	1,360,000	533,000	533,000	1,396,000	1,360,000	1,300,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	1,312,000	524,000	1,360,000	533,000	533,000
Losses charged off	0	0	0	0	0
Recoveries	0	1,000	1,000	2,000	2,000
Balance, end of period	1,396,000	1,300,000	1,396,000	1,300,000	1,360,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						1,396,000	1,360,000	1,300,000
Loans [Abstract]
Ending balance						185,275,000	178,091,000	169,309,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						185,275,000	178,091,000	169,309,000
Residential Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	97,000	87,000	77,000	98,000	135,000
Less [Abstract]
Allowance for loan losses	731,000	757,000	$ 790,000	771,000	771,000	804,000	790,000	818,000
Loans Receivable Additional Information [Abstract]
Maximum Loan-to-value Ratio (in hundredths)			80.00%
Amortization period of loans			twenty five years
Balloon period			five years
Allowance for Loan Losses [Abstract]
Balance, beginning of period	731,000	757,000	$ 790,000	771,000	771,000
Losses charged off	(24,000)	(30,000)	(64,000)	(75,000)	(140,000)
Recoveries	0	4,000	1,000	24,000	24,000
Balance, end of period	804,000	818,000	804,000	818,000	790,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	14,000
Collectively evaluated for impairment						804,000	790,000	804,000
Loans [Abstract]
Ending balance						234,761,000	184,661,000	188,521,000
Ending Balance [Abstract]
Individually evaluated for impairment						411,000	0	225,000
Collectively evaluated for impairment						234,350,000	184,661,000	188,296,000
Unallocated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Allowance for Credit Losses, Period Increase (Decrease)	(89,000)	(609,000)	(109,000)	(270,000)	(690,000)
Less [Abstract]
Allowance for loan losses	212,000	1,261,000	232,000	922,000	922,000	123,000	232,000	652,000
Allowance for Loan Losses [Abstract]
Balance, beginning of period	212,000	1,261,000	232,000	922,000	922,000
Losses charged off	0	0	0	0	0
Recoveries	0	0	0	0	0
Balance, end of period	$ 123,000	$ 652,000	$ 123,000	$ 652,000	$ 232,000
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						123,000	232,000	652,000
Loans [Abstract]
Ending balance						0	0	0
Ending Balance [Abstract]
Individually evaluated for impairment						0	0	0
Collectively evaluated for impairment						$ 0	$ 0	$ 0