Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	$ 497,132		$ 497,132		$ 487,509
Loans, allowance for loan losses	6,650		6,650		6,487
Net loans	490,482		490,482		481,022
Individually evaluated for impairment	8,283		8,283		8,881
Collectively evaluated for impairment	488,849		488,849		478,628
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	562		562		494
Collectively evaluated for impairment	6,088		6,088		5,993
Total	6,650	6,163	6,650	6,163
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	6,545	6,068	6,487	5,915
Charge-offs	(16)	(70)	(75)	(163)
Recoveries	16	15	28	36
Provision	105	150	210	375
Balance	6,650	6,163	6,650	6,163
Minimum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of past due after which loans to be impaired, minimum			90 days
Residential [Member] | First Mortgage [Member] | Minimum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of mortgage on real estate			15 years
Residential [Member] | First Mortgage [Member] | Maximum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of mortgage on real estate			30 years
Home equity [Member] | Second Mortgage [Member] | Maximum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of mortgage on real estate			15 years
Real estate loans [Member] | Residential [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	181,409		181,409		184,034
Individually evaluated for impairment	351		351		94
Collectively evaluated for impairment	181,058		181,058		183,940
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	29		29		13
Collectively evaluated for impairment	758		758		792
Total	786	678	786	678
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	753	921	805	969
Charge-offs	0	(41)	(49)	(101)
Recoveries	0	0	0	0
Provision	33	(202)	30	(190)
Balance	786	678	786	678
Real estate loans [Member] | Commercial and agricultural [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	189,705		189,705		185,050
Individually evaluated for impairment	7,475		7,475		8,270
Collectively evaluated for impairment	182,230		182,230		176,780
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	512		512		433
Collectively evaluated for impairment	3,893		3,893		3,699
Total	4,405	3,912	4,405	3,912
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	4,336	3,698	4,132	3,380
Charge-offs	0	(12)	(2)	(29)
Recoveries	6	0	6	0
Provision	63	226	269	561
Balance	4,405	3,912	4,405	3,912
Real estate loans [Member] | Residential mortgages [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	105,158		105,158		102,711
Real estate loans [Member] | Home equity [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	76,251		76,251		81,323
Real estate loans [Member] | Commercial [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	170,878		170,878		165,826
Real estate loans [Member] | Agricultural [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	18,827		18,827		19,224
Real estate loans [Member] | Construction [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	10,328		10,328		8,481
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	10,328		10,328		8,481
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	19		19		15
Total	19	13	19	13
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	16	13	15	22
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	3	0	4	(9)
Balance	19	13	19	13
Other commercial and agricultural loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	47,067		47,067		44,299
Individually evaluated for impairment	457		457		517
Collectively evaluated for impairment	46,610		46,610		43,782
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	21		21		48
Collectively evaluated for impairment	663		663		626
Total	685	712	685	712
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	671	901	674	983
Charge-offs	0	0	0	0
Recoveries	3	3	6	7
Provision	11	(192)	5	(278)
Balance	685	712	685	712
Consumer [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	11,160		11,160		10,746
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	11,160		11,160		10,746
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	108		108		111
Total	108	109	108	109
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	96	87	111	108
Charge-offs	(16)	(17)	(24)	(33)
Recoveries	7	12	16	29
Provision	21	27	5	5
Balance	108	109	108	109
Other commercial [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	39,820		39,820		37,747
State and political subdivision loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	57,463		57,463		54,899
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	57,463		57,463		54,899
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	246		246		235
Total	246	119	246	119
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	245	139	235	137
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	1	(20)	11	(18)
Balance	246	119	246	119
Other agricultural loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total Loans	7,247		7,247		6,552
Unallocated [Member]
Summary of allowance for loan losses into amount required for loans individually evaluated for impairment and the amount required for loans collectively evaluated for impairment [Abstract]
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	401		401		515
Total	401	620	401	620
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance	428	309	515	316
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision	(27)	311	(114)	304
Balance	$ 401	$ 620	$ 401	$ 620