Loans, Impaired Financing Receivable (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	$ 22,244		$ 27,160
Recorded Investment With No Allowance	14,741		16,802
Recorded Investment With Allowance	6,223		6,648
Total Recorded Investment	20,964		23,450
Related Allowance	721		676
Average Recorded Investment	22,879	$ 24,541
Interest Income Recognized	159	214
Interest Income Recognized Cash Basis	6	5
Real Estate Loans [Member] \| Mortgages [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,239		932
Recorded Investment With No Allowance	856		515
Recorded Investment With Allowance	238		288
Total Recorded Investment	1,094		803
Related Allowance	10		10
Average Recorded Investment	1,103	1,023
Interest Income Recognized	4	4
Interest Income Recognized Cash Basis	0	0
Real Estate Loans [Member] \| Home Equity [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	103		106
Recorded Investment With No Allowance	11		12
Recorded Investment With Allowance	73		75
Total Recorded Investment	84		87
Related Allowance	13		14
Average Recorded Investment	85	107
Interest Income Recognized	1	1
Interest Income Recognized Cash Basis	0	0
Real Estate Loans [Member] \| Commercial [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	11,242		16,326
Recorded Investment With No Allowance	9,635		11,933
Recorded Investment With Allowance	1,089		1,394
Total Recorded Investment	10,724		13,327
Related Allowance	310		216
Average Recorded Investment	12,548	13,795
Interest Income Recognized	119	122
Interest Income Recognized Cash Basis	6	5
Real Estate Loans [Member] \| Agricultural [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	5,569		5,598
Recorded Investment With No Allowance	2,368		2,386
Recorded Investment With Allowance	3,194		3,206
Total Recorded Investment	5,562		5,592
Related Allowance	83		84
Average Recorded Investment	5,575	4,086
Interest Income Recognized	32	51
Interest Income Recognized Cash Basis	0	0
Real Estate Loans [Member] \| Construction [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	0		0
Recorded Investment With No Allowance	0		0
Recorded Investment With Allowance	0		0
Total Recorded Investment	0		0
Related Allowance	0		0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Interest Income Recognized Cash Basis	0	0
Consumer [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	0		0
Recorded Investment With No Allowance	0		0
Recorded Investment With Allowance	0		0
Total Recorded Investment	0		0
Related Allowance	0		0
Average Recorded Investment	0	4
Interest Income Recognized	0	0
Interest Income Recognized Cash Basis	0	0
Other Commercial Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	2,608		2,711
Recorded Investment With No Allowance	1,752		1,836
Recorded Investment With Allowance	320		370
Total Recorded Investment	2,072		2,206
Related Allowance	146		193
Average Recorded Investment	2,137	4,156
Interest Income Recognized	1	26
Interest Income Recognized Cash Basis	0	0
Other Agricultural Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	1,483		1,487
Recorded Investment With No Allowance	119		120
Recorded Investment With Allowance	1,309		1,315
Total Recorded Investment	1,428		1,435
Related Allowance	159		159
Average Recorded Investment	1,431	1,370
Interest Income Recognized	2	10
Interest Income Recognized Cash Basis	0	0
State and Political Subdivision Loans [Member]
Impaired Financing Receivable [Abstract]
Unpaid Principal Balance	0		0
Recorded Investment With No Allowance	0		0
Recorded Investment With Allowance	0		0
Total Recorded Investment	0		0
Related Allowance	0		$ 0
Average Recorded Investment	0	0
Interest Income Recognized	0	0
Interest Income Recognized Cash Basis	$ 0	$ 0

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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- Definition

Amount of interest income recognized on a cash-basis method of accounting that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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Amount of allowance for credit losses related to recorded investment.

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Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

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Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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