Loans, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance for loan losses [Roll Forward]
Balance, beginning of period	$ 3,382	$ 3,373	$ 3,575	$ 3,129
Provision charged to expenses	(12)	372	225	858
Losses charged off	(185)	(103)	(779)	(429)
Recoveries	222	156	386	240
Balance, end of period	3,407	3,798	3,407	3,798
Commercial and Industrial [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	273	273	350	244
Provision charged to expenses	8	162	(84)	236
Losses charged off	0	0	0	(49)
Recoveries	19	12	34	16
Balance, end of period	300	447	300	447
Commercial Secured By Real Estate [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	2,136	2,071	2,179	1,908
Provision charged to expenses	(9)	193	287	478
Losses charged off	(118)	(19)	(462)	(159)
Recoveries	106	80	111	98
Balance, end of period	2,115	2,325	2,115	2,325
Residential Real Estate [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	822	885	885	854
Provision charged to expenses	(139)	(46)	(137)	19
Losses charged off	0	(21)	(135)	(63)
Recoveries	38	43	108	51
Balance, end of period	721	861	721	861
Consumer [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	86	80	96	54
Provision charged to expenses	(6)	36	(3)	85
Losses charged off	(30)	(30)	(84)	(83)
Recoveries	44	9	85	39
Balance, end of period	94	95	94	95
Agricultural [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	61	62	60	66
Provision charged to expenses	113	6	114	2
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	174	68	174	68
Other [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	4	2	5	3
Provision charged to expenses	21	21	48	38
Losses charged off	(37)	(33)	(98)	(75)
Recoveries	15	12	48	36
Balance, end of period	$ 3	$ 2	$ 3	$ 2