Loans, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
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	$ 442		$ 487
Collectively evaluated for impairment	10,005		8,399
Total	10,447	$ 9,979	8,886	$ 8,194	$ 7,359	$ 7,106
Real Estate Loans [Member] | Residential [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	26		32
Collectively evaluated for impairment	1,054		1,032
Total	1,080	1,104	1,064	1,013	990	905
Real Estate Loans [Member] | Commercial [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	67		45
Collectively evaluated for impairment	3,515		3,544
Total	3,582	3,541	3,589	3,615	3,338	3,376
Real Estate Loans [Member] | Agricultural [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	99		54
Collectively evaluated for impairment	2,595		1,440
Total	2,694	2,452	1,494	991	581	409
Real Estate Loans [Member] | Construction [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
Collectively evaluated for impairment	31		47
Total	31	45	47	34	18	24
Consumer [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	2		0
Collectively evaluated for impairment	135		122
Total	137	125	122	109	104	102
Other Commercial Loans [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	208		326
Collectively evaluated for impairment	904		1,001
Total	1,112	1,131	1,327	1,343	1,316	1,183
Other Agricultural Loans [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	40		30
Collectively evaluated for impairment	422		282
Total	462	431	312	299	248	122
State and Political Subdivision Loans [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
Collectively evaluated for impairment	874		833
Total	874	838	833	771	764	593
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
Collectively evaluated for impairment	475		98
Total	$ 475	$ 312	$ 98	$ 19	$ 0	$ 392