Loans and Allowance - Subsequent Default (Details) $ in Thousands	12 Months Ended
Dec. 31, 2017 USD ($) loan	Dec. 31, 2016 USD ($) loan
Financing Receivable, Impaired [Line Items]
Number of Loans \| loan	5	6
Recorded Balance \| $	$ 337	$ 1,265
Commercial and industrial loans
Financing Receivable, Impaired [Line Items]
Number of Loans \| loan		3
Recorded Balance \| $		$ 197
Agriculture production financing and other loans to farmers
Financing Receivable, Impaired [Line Items]
Number of Loans \| loan		1
Recorded Balance \| $		$ 661
Commercial and farmland
Financing Receivable, Impaired [Line Items]
Number of Loans \| loan	1	1
Recorded Balance \| $	$ 14	$ 343
Residential
Financing Receivable, Impaired [Line Items]
Number of Loans \| loan	4	1
Recorded Balance \| $	$ 323	$ 64

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

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- Definition

Amount of investment related to financing receivables modified by troubled debt restructurings within the previous 12 months, for which there was a payment default.

+ References

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