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Loans and ALLL (Credit quality indicators for commercial and agricultural credit exposures) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 1,195,918	$ 1,238,311
Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	725,540	756,686
Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	507,688	506,297
Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	208,395	200,131
Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	9,457	50,258
Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	91,629	100,461
Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	67,872	71,218
Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	23,757	29,243
Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	817,169	857,147
1 - Excellent [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	76	0
1 - Excellent [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
1 - Excellent [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	76	0
1 - Excellent [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
1 - Excellent [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
1 - Excellent [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
1 - Excellent [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
1 - Excellent [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	76	0
2 - High quality [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14,240	15,714
2 - High quality [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,552	2,308
2 - High quality [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	12,688	13,406
2 - High quality [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
2 - High quality [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	547	552
2 - High quality [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	536	541
2 - High quality [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	11	11
2 - High quality [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14,787	16,266
3 - High satisfactory [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	134,698	170,678
3 - High satisfactory [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	74,559	69,327
3 - High satisfactory [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	50,682	51,093
3 - High satisfactory [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	9,457	50,258
3 - High satisfactory [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	15,388	19,723
3 - High satisfactory [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	11,565	14,411
3 - High satisfactory [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,823	5,312
3 - High satisfactory [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	150,086	190,401
4 - Low satisfactory [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	531,880	525,758
4 - Low satisfactory [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	401,410	403,733
4 - Low satisfactory [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	130,470	122,025
4 - Low satisfactory [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
4 - Low satisfactory [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	46,255	52,064
4 - Low satisfactory [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	33,333	34,464
4 - Low satisfactory [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	12,922	17,600
4 - Low satisfactory [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	578,135	577,822
5 - Special mention [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	20,147	21,223
5 - Special mention [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	13,941	15,049
5 - Special mention [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,206	6,174
5 - Special mention [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
5 - Special mention [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	15,797	16,377
5 - Special mention [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	12,490	13,137
5 - Special mention [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,307	3,240
5 - Special mention [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	35,944	37,600
6 - Substandard [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	23,171	21,984
6 - Substandard [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	16,180	15,854
6 - Substandard [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,991	6,130
6 - Substandard [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
6 - Substandard [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	10,591	7,960
6 - Substandard [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	7,173	5,267
6 - Substandard [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,418	2,693
6 - Substandard [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	33,762	29,944
7 - Vulnerable [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,328	1,329
7 - Vulnerable [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	46	26
7 - Vulnerable [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,282	1,303
7 - Vulnerable [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
7 - Vulnerable [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,863	3,595
7 - Vulnerable [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,587	3,208
7 - Vulnerable [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	276	387
7 - Vulnerable [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	4,191	4,924
8 - Doubtful [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
8 - Doubtful [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
8 - Doubtful [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
8 - Doubtful [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
8 - Doubtful [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	188	190
8 - Doubtful [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	188	190
8 - Doubtful [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
8 - Doubtful [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	188	190
Loss [Member] | Total commercial [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Commercial real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Commercial other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Commercial Advances to Mortgage Brokers Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Total agricultural [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Agricultural real estate [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Agricultural other [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Loss [Member] | Commercial And Agricultural Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 0	$ 0

X

- Definition

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+ References

No definition available.

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- Definition

Amount, before allowance for credit loss, of financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=119407570&loc=SL82919230-210447

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