Loans, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Recorded Investment
With no related allowance recorded	$ 23,309		$ 23,309		$ 17,099
With an allowance recorded	1,002		1,002		3,550
Total	24,311		24,311		20,649
Unpaid Principal Balance
With no related allowance recorded	26,090		26,090		18,961
With an allowance recorded	1,051		1,051		3,574
Total	27,141		27,141		22,535
Related Allowance
With an allowance recorded	39		39		191
Average Recorded Investment
With no related allowance recorded	23,179	$ 18,480	21,117	$ 18,513
With an allowance recorded	1,024	4,101	1,038	4,316
Total	24,203	22,581	22,155	22,829
Interest Income Recognized
With no related allowance recorded	392	251	920	956
With an allowance recorded	15	23	46	73
Total	407	274	966	1,029
Cash basis interest expense on impaired loans			85	3
Commercial and industrial [Member]
Recorded Investment
With no related allowance recorded	1,141		1,141		1,015
With an allowance recorded	271		271		296
Total	1,412		1,412		1,311
Unpaid Principal Balance
With no related allowance recorded	1,667		1,667		1,100
With an allowance recorded	277		277		301
Total	1,944		1,944		1,401
Related Allowance
With an allowance recorded	10		10		8
Average Recorded Investment
With no related allowance recorded	1,261	945	950	603
With an allowance recorded	276	306	283	314
Total	1,537	1,251	1,233	917
Interest Income Recognized
With no related allowance recorded	35	10	56	46
With an allowance recorded	4	4	13	13
Total	39	14	69	59
Commercial, secured by real estate [Member]
Recorded Investment
With no related allowance recorded	17,730		17,730		12,677
With an allowance recorded	151		151		2,660
Total	17,881		17,881		15,337
Unpaid Principal Balance
With no related allowance recorded	19,082		19,082		13,608
With an allowance recorded	151		151		2,660
Total	19,233		19,233		16,268
Related Allowance
With an allowance recorded	3		3		146
Average Recorded Investment
With no related allowance recorded	17,364	13,671	16,143	14,099
With an allowance recorded	152	2,970	154	3,085
Total	17,516	16,641	16,297	17,184
Interest Income Recognized
With no related allowance recorded	269	184	657	685
With an allowance recorded	3	11	9	35
Total	272	195	666	720
Residential real estate [Member]
Recorded Investment
With no related allowance recorded	3,854		3,854		2,822
With an allowance recorded	558		558		553
Total	4,412		4,412		3,375
Unpaid Principal Balance
With no related allowance recorded	4,621		4,621		3,516
With an allowance recorded	601		601		572
Total	5,222		5,222		4,088
Related Allowance
With an allowance recorded	26		26		29
Average Recorded Investment
With no related allowance recorded	3,935	3,268	3,420	3,280
With an allowance recorded	573	604	577	634
Total	4,508	3,872	3,997	3,914
Interest Income Recognized
With no related allowance recorded	77	45	174	180
With an allowance recorded	8	7	23	23
Total	85	52	197	203
Consumer [Member]
Recorded Investment
With no related allowance recorded	28		28		6
With an allowance recorded	22		22		41
Total	50		50		47
Unpaid Principal Balance
With no related allowance recorded	28		28		6
With an allowance recorded	22		22		41
Total	50		50		47
Related Allowance
With an allowance recorded	0		0		8
Average Recorded Investment
With no related allowance recorded	68	16	37	24
With an allowance recorded	23	43	24	43
Total	91	59	61	67
Interest Income Recognized
With no related allowance recorded	1	0	2	2
With an allowance recorded	0	1	1	2
Total	1	1	3	4
Agricultural [Member]
Recorded Investment
With no related allowance recorded	177		177		177
With an allowance recorded	0		0		0
Total	177		177		177
Unpaid Principal Balance
With no related allowance recorded	177		177		177
With an allowance recorded	0		0		0
Total	177		177		177
Related Allowance
With an allowance recorded	0		0		0
Average Recorded Investment
With no related allowance recorded	177	142	177	57
With an allowance recorded	0	178	0	240
Total	177	320	177	297
Interest Income Recognized
With no related allowance recorded	0	0	0	0
With an allowance recorded	0	0	0	0
Total	0	0	0	0
Other [Member]
Recorded Investment
With no related allowance recorded	379		379		402
With an allowance recorded	0		0		0
Total	379		379		402
Unpaid Principal Balance
With no related allowance recorded	515		515		554
With an allowance recorded	0		0		0
Total	515		515		554
Related Allowance
With an allowance recorded	0		0		$ 0
Average Recorded Investment
With no related allowance recorded	374	438	390	450
With an allowance recorded	0	0	0	0
Total	374	438	390	450
Interest Income Recognized
With no related allowance recorded	10	12	31	43
With an allowance recorded	0	0	0	0
Total	$ 10	$ 12	$ 31	$ 43