Loans and ALLL (Past due and current loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 208	$ 0
Nonaccrual	974	792
Total Past Due and Nonaccrual	5,025	4,798
Current	914,569	845,694
Total	919,594	850,492
Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	194	0
Nonaccrual	127	211
Total Past Due and Nonaccrual	1,304	1,015
Current	499,070	447,366
Total	500,374	448,381
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	127	211
Total Past Due and Nonaccrual	1,020	997
Current	379,769	342,620
Total	380,789	343,617
Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	194	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	284	18
Current	119,301	104,746
Total	119,585	104,764
Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	14	0
Nonaccrual	146	146
Total Past Due and Nonaccrual	943	1,232
Current	125,574	114,679
Total	126,517	115,911
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	146
Total Past Due and Nonaccrual	587	1,232
Current	81,995	75,310
Total	82,582	76,542
Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	14	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	356	0
Current	43,579	39,369
Total	43,935	39,369
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	0
Nonaccrual	701	435
Total Past Due and Nonaccrual	2,755	2,520
Current	252,361	248,981
Total	255,116	251,501
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	0
Nonaccrual	701	429
Total Past Due and Nonaccrual	2,428	2,241
Current	205,928	199,622
Total	208,356	201,863
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	0	6
Total Past Due and Nonaccrual	40	54
Current	8,607	9,325
Total	8,647	9,379
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	0
Total Past Due and Nonaccrual	287	225
Current	37,826	40,034
Total	38,113	40,259
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	0
Total Past Due and Nonaccrual	23	31
Current	37,564	34,668
Total	37,587	34,699
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	0
Total Past Due and Nonaccrual	22	27
Current	33,958	30,839
Total	33,980	30,866
Consumer Unsecured Financing Receivable [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	1	4
Current	3,606	3,829
Total	3,607	3,833
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	3,010	2,566
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	677	523
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	602	505
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	75	18
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	783	196
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	441	196
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	342	0
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	1,527	1,816
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	1,200	1,551
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	40
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	287	225
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	23	31
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	22	27
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1	4
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	833	1,440
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	306	281
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	291	281
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	15	0
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	0	890
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	0	890
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	527	269
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	527	261
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	0	8
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	0
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	0
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	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 0	$ 0