Loans and Allowance - Summary of Troubled Debt Restructurings (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) loan	Mar. 31, 2016 USD ($) loan
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 350	$ 1,203
Post-Modification Recorded Balance	$ 363	$ 1,089
Number of Loans | loan	5	10
Commercial and industrial loans
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance		$ 260
Post-Modification Recorded Balance		$ 260
Number of Loans | loan		3
Agricultural production financing and other loans to farmers
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance		$ 465
Post-Modification Recorded Balance		$ 331
Number of Loans | loan		2
Commercial and farmland
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 107	$ 352
Post-Modification Recorded Balance	$ 241	$ 352
Number of Loans | loan	3	1
Real estate loans - Residential
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 121	$ 113
Post-Modification Recorded Balance	$ 122	$ 133
Number of Loans | loan	2	3
Real estate loans - Home Equity
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance	$ 122
Post-Modification Recorded Balance
Number of Loans | loan
Individuals' loans for household and other personal expenditures
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Balance		$ 13
Post-Modification Recorded Balance		$ 13
Number of Loans | loan		1