Loans and ALLL (Past due and current loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 0	$ 148
Nonaccrual	792	4,044
Total Past Due and Nonaccrual	4,798	9,124
Current	845,694	827,426
Total	850,492	836,550
Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	2
Nonaccrual	211	2,880
Total Past Due and Nonaccrual	1,015	4,496
Current	447,366	428,774
Total	448,381	433,270
Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	211	2,764
Total Past Due and Nonaccrual	997	4,201
Current	342,620	310,173
Total	343,617	314,374
Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	2
Nonaccrual	0	116
Total Past Due and Nonaccrual	18	295
Current	104,746	118,601
Total	104,764	118,896
Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	146	106
Total Past Due and Nonaccrual	1,232	309
Current	114,679	104,412
Total	115,911	104,721
Agricultural real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	146	106
Total Past Due and Nonaccrual	1,232	207
Current	75,310	70,990
Total	76,542	71,197
Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	0	102
Current	39,369	33,422
Total	39,369	33,524
Total residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	146
Nonaccrual	435	1,048
Total Past Due and Nonaccrual	2,520	4,181
Current	248,981	261,974
Total	251,501	266,155
Residential real estate senior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	146
Nonaccrual	429	668
Total Past Due and Nonaccrual	2,241	3,060
Current	199,622	211,698
Total	201,863	214,758
Residential real estate junior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	6	130
Total Past Due and Nonaccrual	54	383
Current	9,325	10,750
Total	9,379	11,133
Residential real estate home equity lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	0	250
Total Past Due and Nonaccrual	225	738
Current	40,034	39,526
Total	40,259	40,264
Total consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	0	10
Total Past Due and Nonaccrual	31	138
Current	34,668	32,266
Total	34,699	32,404
Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	0	10
Total Past Due and Nonaccrual	27	119
Current	30,839	28,328
Total	30,866	28,447
Consumer unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	4	19
Current	3,829	3,938
Total	3,833	3,957
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	2,566	4,161
Financing Receivables, 30 to 59 Days Past Due [Member] | Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	523	1,308
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	505	1,155
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	18	153
Financing Receivables, 30 to 59 Days Past Due [Member] | Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	196	203
Financing Receivables, 30 to 59 Days Past Due [Member] | Agricultural real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	196	101
Financing Receivables, 30 to 59 Days Past Due [Member] | Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	102
Financing Receivables, 30 to 59 Days Past Due [Member] | Total residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,816	2,524
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate senior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,551	1,821
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate junior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	40	235
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential real estate home equity lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	225	468
Financing Receivables, 30 to 59 Days Past Due [Member] | Total consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	31	126
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	27	107
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	4	19
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,440	771
Financing Receivables, 60 to 89 Days Past Due [Member] | Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	281	306
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	281	282
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	24
Financing Receivables, 60 to 89 Days Past Due [Member] | Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	890	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Agricultural real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	890	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Total residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	269	463
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate senior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	261	425
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate junior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	8	18
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate home equity lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	20
Financing Receivables, 60 to 89 Days Past Due [Member] | Total consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	2
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	2
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer unsecured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 0	$ 0