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Loans and ALLL (Past due and current loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	$ 0	$ 0
Nonaccrual	4,946	6,535
Total Past Due and Nonaccrual	7,217	11,405
Current	1,296,091	1,175,165
Total	1,303,308	1,186,570
Total commercial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	1,364	1,621
Total Past Due and Nonaccrual	2,082	2,477
Current	819,020	698,464
Total	821,102	700,941
Commercial real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	27	390
Total Past Due and Nonaccrual	178	559
Current	499,208	509,594
Total	499,386	510,153
Commercial other [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	1,337	1,231
Total Past Due and Nonaccrual	1,904	1,918
Current	244,796	153,347
Total	246,700	155,265
Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	0	0
Current	75,016	35,523
Total	75,016	35,523
Total agricultural [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	3,538	4,285
Total Past Due and Nonaccrual	3,903	4,285
Current	98,360	112,635
Total	102,263	116,920
Agricultural real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	3,101	2,711
Total Past Due and Nonaccrual	3,466	2,711
Current	68,473	77,316
Total	71,939	80,027
Agricultural other [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	437	1,574
Total Past Due and Nonaccrual	437	1,574
Current	29,887	35,319
Total	30,324	36,893
Total residential real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	44	629
Total Past Due and Nonaccrual	1,160	4,572
Current	303,399	293,997
Total	304,559	298,569
Residential real estate senior liens [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	44	557
Total Past Due and Nonaccrual	1,143	4,278
Current	267,160	253,894
Total	268,303	258,172
Residential real estate junior liens [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	17	65
Current	4,249	5,766
Total	4,266	5,831
Residential real estate home equity lines of credit [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	0	72
Total Past Due and Nonaccrual	0	229
Current	31,990	34,337
Total	31,990	34,566
Total Consumer [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	72	71
Current	75,312	70,069
Total	75,384	70,140
Consumer secured [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	68	68
Current	71,762	66,547
Total	71,830	66,615
Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Nonaccrual	0	0
Total Past Due and Nonaccrual	4	3
Current	3,550	3,522
Total	3,554	3,525
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,968	4,426
Financial Asset, 30 to 59 Days Past Due [Member] | Total commercial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	718	670
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	151	139
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial other [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	567	531
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Total agricultural [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	270	0
Financial Asset, 30 to 59 Days Past Due [Member] | Agricultural real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	270	0
Financial Asset, 30 to 59 Days Past Due [Member] | Agricultural other [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Total residential real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	908	3,685
Financial Asset, 30 to 59 Days Past Due [Member] | Residential real estate senior liens [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	891	3,463
Financial Asset, 30 to 59 Days Past Due [Member] | Residential real estate junior liens [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	17	65
Financial Asset, 30 to 59 Days Past Due [Member] | Residential real estate home equity lines of credit [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	157
Financial Asset, 30 to 59 Days Past Due [Member] | Total Consumer [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	72	71
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer secured [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	68	68
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	4	3
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	303	444
Financial Asset, 60 to 89 Days Past Due [Member] | Total commercial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	186
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	30
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial other [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	156
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Total agricultural [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	95	0
Financial Asset, 60 to 89 Days Past Due [Member] | Agricultural real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	95	0
Financial Asset, 60 to 89 Days Past Due [Member] | Agricultural other [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Total residential real estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	208	258
Financial Asset, 60 to 89 Days Past Due [Member] | Residential real estate senior liens [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	208	258
Financial Asset, 60 to 89 Days Past Due [Member] | Residential real estate junior liens [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Residential real estate home equity lines of credit [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Total Consumer [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer secured [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Unsecured Financing Receivable [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 0	$ 0

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