Loans and ALLL (Past due and current loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 0	$ 113
Nonaccrual	6,535	7,260
Total Past Due and Nonaccrual	11,405	11,412
Current	1,175,165	1,117,295
Total	1,186,570	1,128,707
Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	1,621	1,757
Total Past Due and Nonaccrual	2,477	2,722
Current	698,464	656,807
Total	700,941	659,529
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	390	334
Total Past Due and Nonaccrual	559	394
Current	509,594	497,293
Total	510,153	497,687
Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	0
Nonaccrual	1,231	1,423
Total Past Due and Nonaccrual	1,918	2,328
Current	153,347	147,721
Total	155,265	150,049
Commercial Advances to Mortgage Brokers Segment [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	0
Current	35,523	11,793
Total	35,523	11,793
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	4,285	4,949
Total Past Due and Nonaccrual	4,285	5,377
Current	112,635	121,784
Total	116,920	127,161
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	2,711	2,716
Total Past Due and Nonaccrual	2,711	3,144
Current	77,316	84,176
Total	80,027	87,320
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	1,574	2,233
Total Past Due and Nonaccrual	1,574	2,233
Current	35,319	37,608
Total	36,893	39,841
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	113
Nonaccrual	629	554
Total Past Due and Nonaccrual	4,572	3,208
Current	293,997	272,135
Total	298,569	275,343
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	113
Nonaccrual	557	554
Total Past Due and Nonaccrual	4,278	3,124
Current	253,894	233,438
Total	258,172	236,562
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	0
Total Past Due and Nonaccrual	65	8
Current	5,766	6,001
Total	5,831	6,009
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	72	0
Total Past Due and Nonaccrual	229	76
Current	34,337	32,696
Total	34,566	32,772
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	71	105
Current	70,069	66,569
Total	70,140	66,674
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	68	95
Current	66,547	62,721
Total	66,615	62,816
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	3	10
Current	3,522	3,848
Total	3,525	3,858
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	4,426	3,202
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	670	337
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	139	60
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	531	277
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	0	0
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	0	428
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	0	428
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	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	3,685	2,332
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	3,463	2,254
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	65	2
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	157	76
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	71	105
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	68	95
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	3	10
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	444	837
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	186	628
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	30	0
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	156	628
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Advances to Mortgage Brokers Segment [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 agricultural [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] | Agricultural real estate [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] | 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	258	209
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	258	203
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	6
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 [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	$ 0	$ 0