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Loans and ALLL (Summary of information pertaining to TDRs) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) loan	Mar. 31, 2017 USD ($) loan
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	7	3
Pre-Modification Recorded Investment	$ 2,483	$ 235
Post-Modification Recorded Investment	$ 2,483	$ 235
Interest Rate Below Market Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	1
Pre-Modification Recorded Investment	$ 272	$ 8
Below Market Interest Rate and Extension of Amortization Period [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	5	2
Pre-Modification Recorded Investment	$ 2,211	$ 227
Commercial other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	3	2
Pre-Modification Recorded Investment	$ 1,255	$ 227
Post-Modification Recorded Investment	$ 1,255	$ 227
Commercial other [Member] | Interest Rate Below Market Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0
Pre-Modification Recorded Investment	$ 174	$ 0
Commercial other [Member] | Below Market Interest Rate and Extension of Amortization Period [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	2
Pre-Modification Recorded Investment	$ 1,081	$ 227
Agricultural other [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	0
Pre-Modification Recorded Investment	$ 1,061	$ 0
Post-Modification Recorded Investment	$ 1,061	$ 0
Agricultural other [Member] | Interest Rate Below Market Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0
Pre-Modification Recorded Investment	$ 98	$ 0
Agricultural other [Member] | Below Market Interest Rate and Extension of Amortization Period [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	1	0
Pre-Modification Recorded Investment	$ 963	$ 0
Residential real estate senior liens [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	0
Pre-Modification Recorded Investment	$ 167	$ 0
Post-Modification Recorded Investment	$ 167	$ 0
Residential real estate senior liens [Member] | Interest Rate Below Market Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0
Pre-Modification Recorded Investment	$ 0	$ 0
Residential real estate senior liens [Member] | Below Market Interest Rate and Extension of Amortization Period [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	0
Pre-Modification Recorded Investment	$ 167	$ 0
Residential real estate junior liens [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1
Pre-Modification Recorded Investment	$ 0	$ 8
Post-Modification Recorded Investment	$ 0	$ 8
Residential real estate junior liens [Member] | Interest Rate Below Market Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1
Pre-Modification Recorded Investment	$ 0	$ 8
Residential real estate junior liens [Member] | Below Market Interest Rate and Extension of Amortization Period [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	0
Pre-Modification Recorded Investment	$ 0	$ 0
Total residential real estate [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	1
Pre-Modification Recorded Investment	$ 167	$ 8
Post-Modification Recorded Investment	$ 167	$ 8
Total residential real estate [Member] | Interest Rate Below Market Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	0	1
Pre-Modification Recorded Investment	$ 0	$ 8
Total residential real estate [Member] | Below Market Interest Rate and Extension of Amortization Period [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans | loan	2	0
Pre-Modification Recorded Investment	$ 167	$ 0

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953676-111524

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
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-Section 50
-Paragraph 33
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-Name Accounting Standards Codification
-Topic 310
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-Section 50
-Paragraph 33
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