Loans and Allowance - Summary of Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) loan	Dec. 31, 2017 USD ($) loan
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 721	$ 3,004
Post-Modification Recorded Balance	$ 719	$ 2,902
Number of Loans | loan	18	34
Commercial and industrial loans
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance		$ 599
Post-Modification Recorded Balance		$ 376
Number of Loans | loan		3
Agriculture production financing and other loans to farmers
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance		$ 387
Post-Modification Recorded Balance		$ 387
Number of Loans | loan		3
Commercial and farmland
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 85	$ 1,022
Post-Modification Recorded Balance	$ 85	$ 1,156
Number of Loans | loan	1	8
Residential
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 490	$ 788
Post-Modification Recorded Balance	$ 487	$ 862
Number of Loans | loan	11	15
Home equity
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 81	$ 195
Post-Modification Recorded Balance	$ 81	$ 107
Number of Loans | loan	3	4
Individuals' loans for household and other personal expenditures
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 65	$ 13
Post-Modification Recorded Balance	$ 66	$ 14
Number of Loans | loan	3	1