Loans and Allowance - Summary of Troubled Debt Restructurings by Modification Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Financing Receivable, Modifications [Line Items]
Modification	$ 363	$ 1,078
Term Modification
Financing Receivable, Modifications [Line Items]
Modification
Rate Modification
Financing Receivable, Modifications [Line Items]
Modification	122	467
Combination
Financing Receivable, Modifications [Line Items]
Modification	241	611
Commercial and industrial loans
Financing Receivable, Modifications [Line Items]
Modification		260
Commercial and industrial loans | Term Modification
Financing Receivable, Modifications [Line Items]
Modification
Commercial and industrial loans | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification
Commercial and industrial loans | Combination
Financing Receivable, Modifications [Line Items]
Modification		260
Agricultural production financing and other loans to farmers
Financing Receivable, Modifications [Line Items]
Modification		331
Agricultural production financing and other loans to farmers | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification		331
Commercial and farmland
Financing Receivable, Modifications [Line Items]
Modification	241	351
Commercial and farmland | Term Modification
Financing Receivable, Modifications [Line Items]
Modification
Commercial and farmland | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification
Commercial and farmland | Combination
Financing Receivable, Modifications [Line Items]
Modification	241	351
Real estate loans - Residential
Financing Receivable, Modifications [Line Items]
Modification	122	123
Real estate loans - Residential | Term Modification
Financing Receivable, Modifications [Line Items]
Modification
Real estate loans - Residential | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification	122	123
Real estate loans - Residential | Combination
Financing Receivable, Modifications [Line Items]
Modification
Individuals' loans for household and other personal expenditures
Financing Receivable, Modifications [Line Items]
Modification		13
Individuals' loans for household and other personal expenditures | Rate Modification
Financing Receivable, Modifications [Line Items]
Modification		13
Individuals' loans for household and other personal expenditures | Combination
Financing Receivable, Modifications [Line Items]
Modification