Loans and Allowance - Composition of Loan Portfolio by Loan Class (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 9,356,241	$ 9,241,861
Commercial and industrial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	2,826,660	2,714,565
Agricultural land, production and other loans to farmers
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	209,077	246,442
Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	552,975	523,066
Commercial real estate, non-owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	2,073,197	2,135,459
Commercial real estate, owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	974,521	986,720
Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	1,226,695	1,159,127
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	512,641	523,754
Individuals' loans for household and other personal expenditures
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	147,593	146,092
Public finance and other commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Loans	$ 832,882	$ 806,636