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Loans and ALLL (Past due and current loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 274	$ 395
Nonaccrual	7,136	3,027
Total Past Due and Nonaccrual	11,952	9,836
Current	1,127,978	1,081,683
Total	1,139,930	1,091,519
Total commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	72
Nonaccrual	1,140	729
Total Past Due and Nonaccrual	3,084	2,518
Current	665,831	632,241
Total	668,915	634,759
Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	54
Nonaccrual	897	729
Total Past Due and Nonaccrual	1,323	1,403
Current	503,563	480,251
Total	504,886	481,654
Commercial other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	18
Nonaccrual	243	0
Total Past Due and Nonaccrual	1,761	1,115
Current	146,637	139,909
Total	148,398	141,024
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	15,631	12,081
Total	15,631	12,081
Total agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	62	104
Nonaccrual	5,298	1,950
Total Past Due and Nonaccrual	5,663	2,367
Current	123,569	125,902
Total	129,232	128,269
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	2,881	1,531
Total Past Due and Nonaccrual	2,974	1,805
Current	84,760	86,360
Total	87,734	88,165
Agricultural other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	62	104
Nonaccrual	2,417	419
Total Past Due and Nonaccrual	2,689	562
Current	38,809	39,542
Total	41,498	40,104
Total residential real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	212	209
Nonaccrual	698	348
Total Past Due and Nonaccrual	3,137	4,881
Current	273,767	267,487
Total	276,904	272,368
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	212	132
Nonaccrual	698	325
Total Past Due and Nonaccrual	2,629	4,409
Current	233,325	225,007
Total	235,954	229,416
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	23
Total Past Due and Nonaccrual	9	102
Current	6,157	6,812
Total	6,166	6,914
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	77
Nonaccrual	0	0
Total Past Due and Nonaccrual	499	370
Current	34,285	35,668
Total	34,784	36,038
Total Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	10
Nonaccrual	0	0
Total Past Due and Nonaccrual	68	70
Current	64,811	56,053
Total	64,879	56,123
Consumer secured [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	0	10
Nonaccrual	0	0
Total Past Due and Nonaccrual	66	57
Current	60,956	52,005
Total	61,022	52,062
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	2	13
Current	3,855	4,048
Total	3,857	4,061
Financing Receivables, 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	3,052	5,617
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	1,129	1,364
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	426	295
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	703	1,069
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	120	123
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	70	84
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	50	39
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	1,735	4,080
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	1,261	3,718
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	9	69
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	465	293
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	68	50
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	66	37
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	2	13
Financing Receivables, 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Recorded Investment, Past Due	1,490	797
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	815	353
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	0	325
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	815	28
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	183	190
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	23	190
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	160	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	492	244
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	458	234
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	10
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	34	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	10
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	10
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

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