Loans, Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Recorded Investment
With no related allowance recorded	$ 18,653		$ 18,653		$ 18,357
With an allowance recorded	4,079		4,079		5,810
Total	22,732		22,732		24,167
Unpaid Principal Balance
With no related allowance recorded	21,140		21,140		21,061
With an allowance recorded	4,109		4,109		6,066
Total	25,249		25,249		27,127
Related Allowance
With an allowance recorded	368		368		469
Average Recorded Investment
With no related allowance recorded	18,480	$ 21,612	18,513	$ 22,562
With an allowance recorded	4,101	4,599	4,316	4,083
Total	22,581	26,211	22,829	26,645
Interest Income Recognized
With no related allowance recorded	251	408	956	1,507
With an allowance recorded	23	55	73	123
Total	274	463	1,029	1,630
Cash basis interest expense on impaired loans			1	48
Commercial and industrial [Member]
Recorded Investment
With no related allowance recorded	1,016		1,016		109
With an allowance recorded	303		303		326
Total	1,319		1,319		435
Unpaid Principal Balance
With no related allowance recorded	1,154		1,154		263
With an allowance recorded	308		308		326
Total	1,462		1,462		589
Related Allowance
With an allowance recorded	7		7		9
Average Recorded Investment
With no related allowance recorded	945	1,356	603	1,167
With an allowance recorded	306	476	314	400
Total	1,251	1,832	917	1,567
Interest Income Recognized
With no related allowance recorded	10	34	46	89
With an allowance recorded	4	5	13	15
Total	14	39	59	104
Commercial, secured by real estate [Member]
Recorded Investment
With no related allowance recorded	13,722		13,722		14,195
With an allowance recorded	2,958		2,958		4,690
Total	16,680		16,680		18,885
Unpaid Principal Balance
With no related allowance recorded	14,854		14,854		15,522
With an allowance recorded	2,957		2,957		4,946
Total	17,811		17,811		20,468
Related Allowance
With an allowance recorded	182		182		347
Average Recorded Investment
With no related allowance recorded	13,671	15,594	14,099	16,654
With an allowance recorded	2,970	3,383	3,085	2,960
Total	16,641	18,977	17,184	19,614
Interest Income Recognized
With no related allowance recorded	184	236	685	897
With an allowance recorded	11	41	35	82
Total	195	277	720	979
Residential real estate [Member]
Recorded Investment
With no related allowance recorded	3,272		3,272		3,238
With an allowance recorded	598		598		751
Total	3,870		3,870		3,989
Unpaid Principal Balance
With no related allowance recorded	4,341		4,341		4,286
With an allowance recorded	624		624		751
Total	4,965		4,965		5,037
Related Allowance
With an allowance recorded	49		49		100
Average Recorded Investment
With no related allowance recorded	3,268	3,769	3,280	3,809
With an allowance recorded	604	695	634	680
Total	3,872	4,464	3,914	4,489
Interest Income Recognized
With no related allowance recorded	45	113	180	306
With an allowance recorded	7	8	23	24
Total	52	121	203	330
Consumer [Member]
Recorded Investment
With no related allowance recorded	10		10		26
With an allowance recorded	43		43		43
Total	53		53		69
Unpaid Principal Balance
With no related allowance recorded	10		10		27
With an allowance recorded	43		43		43
Total	53		53		70
Related Allowance
With an allowance recorded	9		9		13
Average Recorded Investment
With no related allowance recorded	16	29	24	41
With an allowance recorded	43	45	43	43
Total	59	74	67	84
Interest Income Recognized
With no related allowance recorded	0	7	2	22
With an allowance recorded	1	1	2	2
Total	1	8	4	24
Agricultural [Member]
Recorded Investment
With no related allowance recorded	190		190		334
With an allowance recorded	177		177		0
Total	367		367		334
Unpaid Principal Balance
With no related allowance recorded	190		190		334
With an allowance recorded	177		177		0
Total	367		367		334
Related Allowance
With an allowance recorded	121		121		0
Average Recorded Investment
With no related allowance recorded	142	384	57	403
With an allowance recorded	178	0	240	0
Total	320	384	297	403
Interest Income Recognized
With no related allowance recorded	0	0	0	135
With an allowance recorded	0	0	0	0
Total	0	0	0	135
Other [Member]
Recorded Investment
With no related allowance recorded	443		443		455
With an allowance recorded	0		0		0
Total	443		443		455
Unpaid Principal Balance
With no related allowance recorded	591		591		629
With an allowance recorded	0		0		0
Total	591		591		629
Related Allowance
With an allowance recorded	0		0		$ 0
Average Recorded Investment
With no related allowance recorded	438	480	450	488
With an allowance recorded	0	0	0	0
Total	438	480	450	488
Interest Income Recognized
With no related allowance recorded	12	18	43	58
With an allowance recorded	0	0	0	0
Total	$ 12	$ 18	$ 43	$ 58