Loans, Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Allowance for loan losses [Roll Forward]
Balance, beginning of period	$ 3,403	$ 3,575
Provision charged to expenses	79	15
Losses charged off	(106)	(354)
Recoveries	153	92
Balance, end of period	3,529	3,328
Commercial and Industrial [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	378	350
Provision charged to expenses	15	(2)
Losses charged off	0	0
Recoveries	0	5
Balance, end of period	393	353
Commercial Secured By Real Estate [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	2,178	2,179
Provision charged to expenses	(131)	90
Losses charged off	(29)	(262)
Recoveries	125	0
Balance, end of period	2,143	2,007
Residential Real Estate [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	717	885
Provision charged to expenses	186	(107)
Losses charged off	(35)	(17)
Recoveries	1	48
Balance, end of period	869	809
Consumer [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	76	96
Provision charged to expenses	8	23
Losses charged off	(11)	(45)
Recoveries	5	17
Balance, end of period	78	91
Agricultural [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	53	60
Provision charged to expenses	(9)	6
Losses charged off	0	0
Recoveries	0	0
Balance, end of period	44	66
Other [Member]
Allowance for loan losses [Roll Forward]
Balance, beginning of period	1	5
Provision charged to expenses	10	5
Losses charged off	(31)	(30)
Recoveries	22	22
Balance, end of period	$ 2	$ 2