Credit Quality - Schedule of Nonaccrual Loans, Segregated by Class of Loans and Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Financing Receivable, Past Due [Line Items]
Nonaccruals	$ 99,907	$ 96,492
With No Related Allowance for Credit Losses	96,906	94,029
Other Commercial [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	6,705	5,978
With No Related Allowance for Credit Losses	4,242	3,515
Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	13,840	15,423
With No Related Allowance for Credit Losses	13,840	15,423
Owner-Occupied [Member] \| Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	1,444	1,749
With No Related Allowance for Credit Losses	1,444	1,749
Nonowner-Occupied [Member] \| Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	74,641	71,038
With No Related Allowance for Credit Losses	74,641	71,038
Construction & land development [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	2,681	1,301
With No Related Allowance for Credit Losses	2,143	1,301
Bankcard [Member] \| Consumer [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	0	0
With No Related Allowance for Credit Losses	0	0
Other Consumer [Member] \| Consumer [Member]
Financing Receivable, Past Due [Line Items]
Nonaccruals	596	1,003
With No Related Allowance for Credit Losses	$ 596	$ 1,003