Allowance for Credit Losses - Schedule Of Credit Losses Related To Accrued Interest Receivables and Written Off (Detail) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Accrued Interest Receivables And Written Off Status [Line Items]
Total	$ 88,374	$ 95,960
Other Commercial [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	10,739	11,822
Residential Real Estate [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	22,218	21,643
Owner-Occupied [Member] \| Commercial Real Estate [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	6,147	6,922
Nonowner-Occupied [Member] \| Commercial Real Estate [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	33,254	37,086
Construction [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	13,491	16,046
Bankcard [Member] \| Consumer [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	0	0
Other Consumer [Member] \| Consumer [Member]
Accrued Interest Receivables And Written Off Status [Line Items]
Accrued Interest Receivable	$ 2,525	$ 2,441