Loans and ALLL (Past due and current loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	$ 0	$ 148
Nonaccrual	796	4,044
Total Past Due and Nonaccrual	3,799	9,124
Current	829,548	824,458
Total	833,347	833,582
Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	2
Nonaccrual	284	2,880
Total Past Due and Nonaccrual	1,006	4,496
Current	432,063	427,465
Total	433,069	431,961
Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	284	2,764
Total Past Due and Nonaccrual	675	4,201
Current	331,556	310,173
Total	332,231	314,374
Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	2
Nonaccrual	0	116
Total Past Due and Nonaccrual	331	295
Current	100,507	117,292
Total	100,838	117,587
Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	278	106
Total Past Due and Nonaccrual	703	309
Current	115,590	104,412
Total	116,293	104,721
Agricultural real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	274	106
Total Past Due and Nonaccrual	274	207
Current	74,097	70,990
Total	74,371	71,197
Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	4	0
Total Past Due and Nonaccrual	429	102
Current	41,493	33,422
Total	41,922	33,524
Total residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	146
Nonaccrual	234	1,048
Total Past Due and Nonaccrual	2,030	4,181
Current	247,820	260,414
Total	249,850	264,595
Residential real estate senior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	146
Nonaccrual	234	668
Total Past Due and Nonaccrual	1,931	3,060
Current	197,687	210,138
Total	199,618	213,198
Residential real estate junior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	0	130
Total Past Due and Nonaccrual	74	383
Current	9,599	10,750
Total	9,673	11,133
Residential real estate home equity lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	0	250
Total Past Due and Nonaccrual	25	738
Current	40,534	39,526
Total	40,559	40,264
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	0	10
Total Past Due and Nonaccrual	60	138
Current	34,075	32,167
Total	34,135	32,305
Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	0	10
Total Past Due and Nonaccrual	56	119
Current	30,186	28,229
Total	30,242	28,348
Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Pass Due: 90 Days or More	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	4	19
Current	3,889	3,938
Total	3,893	3,957
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	2,941	4,161
Financing Receivables, 30 to 59 Days Past Due [Member] | Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	714	1,308
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	391	1,155
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	323	153
Financing Receivables, 30 to 59 Days Past Due [Member] | Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	425	203
Financing Receivables, 30 to 59 Days Past Due [Member] | Agricultural real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	0	101
Financing Receivables, 30 to 59 Days Past Due [Member] | Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	425	102
Financing Receivables, 30 to 59 Days Past Due [Member] | Total residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	1,742	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]
Accruing Interest and Past Due	1,649	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]
Accruing Interest and Past Due	68	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]
Accruing Interest and Past Due	25	468
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	60	126
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	56	107
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	4	19
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	62	771
Financing Receivables, 60 to 89 Days Past Due [Member] | Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	8	306
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	0	282
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	8	24
Financing Receivables, 60 to 89 Days Past Due [Member] | Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Agricultural real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and 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]
Accruing Interest and Past Due	54	463
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate senior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	48	425
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential real estate junior liens [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	6	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]
Accruing Interest and Past Due	0	20
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	0	2
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	0	2
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing Interest and Past Due	$ 0	$ 0