Loans and Allowance - Summary of Non-Accrual Loans by Loan Class (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 22,728	$ 26,148
Commercial and industrial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	2,065	1,803
Agricultural production financing and other loans to farmers
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	3,150	679
Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	1,027	8,667
Commercial and farmland
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	9,265	8,156
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	5,381	4,966
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	1,737	1,481
Individuals' loans for household and other personal expenditures
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	103	42
Public finance and other commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual loans	$ 0	$ 354