Loans, Past Due (Details) (USD $) In Thousands, unless otherwise specified			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Minimum [Member]	Sep. 30, 2012 Loans considered non-accrual [Member]	Dec. 31, 2011 Loans considered non-accrual [Member]	Sep. 30, 2012 Loans still accruing [Member]	Dec. 31, 2011 Loans still accruing [Member]	Sep. 30, 2012 Real estate loans [Member] Residential [Member]	Dec. 31, 2011 Real estate loans [Member] Residential [Member]	Sep. 30, 2012 Real estate loans [Member] Commercial and agricultural [Member]	Dec. 31, 2011 Real estate loans [Member] Commercial and agricultural [Member]	Sep. 30, 2012 Real estate loans [Member] Residential mortgages [Member]	Dec. 31, 2011 Real estate loans [Member] Residential mortgages [Member]	Sep. 30, 2012 Real estate loans [Member] Home equity [Member]	Dec. 31, 2011 Real estate loans [Member] Home equity [Member]	Sep. 30, 2012 Real estate loans [Member] Commercial [Member]	Dec. 31, 2011 Real estate loans [Member] Commercial [Member]	Sep. 30, 2012 Real estate loans [Member] Agricultural [Member]	Dec. 31, 2011 Real estate loans [Member] Agricultural [Member]	Sep. 30, 2012 Real estate loans [Member] Construction [Member]	Dec. 31, 2011 Real estate loans [Member] Construction [Member]	Sep. 30, 2012 Commercial and other loans [Member]	Dec. 31, 2011 Commercial and other loans [Member]	Sep. 30, 2012 Consumer [Member]	Dec. 31, 2011 Consumer [Member]	Sep. 30, 2012 Other commercial [Member]	Dec. 31, 2011 Other commercial [Member]	Sep. 30, 2012 Other agricultural loans [Member]	Dec. 31, 2011 Other agricultural loans [Member]	Sep. 30, 2012 State and political subdivision loans [Member]	Dec. 31, 2011 State and political subdivision loans [Member]
Recorded investment of past due [Abstract]
30 to 59 Days Past Due	$ 1,587	$ 1,324		$ 171	$ 0	$ 1,416	$ 1,324					$ 913	$ 428	$ 275	$ 339	$ 336	$ 319	$ 0	$ 143	$ 0	$ 0			$ 8	$ 86	$ 55	$ 9	$ 0	$ 0	$ 0	$ 0
60 to 89 Days Past Due	355	510		65	0	290	510					3	91	65	0	129	412	0	0	0	0			48	7	110	0	0	0	0	0
90 Days Or Greater	2,973	3,875		2,534	3,600	439	275					254	398	197	180	2,193	2,794	0		0	0			2	0	327	503	0	0	0	0
Total Past Due	4,915	5,709		2,770	3,600	2,145	2,109					1,170	917	537	519	2,658	3,525	0	143	0	0			58	93	492	512	0	0	0	0
Current	494,311	481,800		5,485	5,565	488,826	476,235					107,425	101,794	73,867	80,804	166,949	162,301	18,300	19,081	12,131	8,481			10,469	10,653	38,990	37,235	7,172	6,552	59,008	54,899
Total Financing Receivable	499,226	487,509		8,255	9,165	490,971	478,344	182,999	184,034	187,907	185,050	108,595	102,711	74,404	81,323	169,607	165,826	18,300	19,224	12,131	8,481	46,654	44,299	10,527	10,746	39,482	37,747	7,172	6,552	59,008	54,899
90 Days and Accruing	439	275										78	60	64	39	295	176	0	0	0	0			2	0	0	0	0	0	0	0
Period of past due after which loans considered as non accrual			90 days
Financing receivables on nonaccrual status [Abstract]
Financing receivable nonaccrual status	$ 8,255	$ 9,165										$ 486	$ 413	$ 208	$ 141	$ 7,224	$ 8,094	$ 0	$ 0	$ 0	$ 0			$ 0	$ 0	$ 337	$ 517	$ 0	$ 0	$ 0	$ 0