Loans and Allowance - Summary of Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) loan	Dec. 31, 2015 USD ($) loan
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 7,165	$ 5,960
Post-Modification Recorded Balance	$ 7,035	$ 6,601
Number of Loans | loan	37	23
Commercial and industrial loans
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 410	$ 4,111
Post-Modification Recorded Balance	$ 410	$ 2,115
Number of Loans | loan	4	7
Agriculture production financing and other loans to farmers
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 1,368
Post-Modification Recorded Balance	$ 1,234
Number of Loans | loan	4
Construction
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance		$ 79
Post-Modification Recorded Balance		$ 80
Number of Loans | loan		1
Commercial and farmland
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 3,978	$ 1,281
Post-Modification Recorded Balance	$ 3,954	$ 3,024
Number of Loans | loan	7	3
Residential
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 1,126	$ 200
Post-Modification Recorded Balance	$ 1,183	$ 1,113
Number of Loans | loan	17	10
Home equity
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 266	$ 263
Post-Modification Recorded Balance	$ 244	$ 242
Number of Loans | loan	4	1
Individuals' loans for household and other personal expenditures
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 17	$ 26
Post-Modification Recorded Balance	$ 10	$ 27
Number of Loans | loan	1	1