Derivative Financial Instruments - Schedule of Amounts Related to Non-Hedging Interest Rate and Commodity Derivatives (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
States and political subdivisions [Member] | Designated as Hedging Instrument [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Interest income on tax-exempt securities (net ineffective portion of hedge)	$ (18)	$ 0	$ 10	$ 0
Interest Rate Contract [Member] | Other Non-Interest Income [Member] | Non Designated as Hedging Instrument [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount of gain (loss) included in income (expense)	1,312	733	2,844	1,122
Interest Rate Contract [Member] | Other Non-Interest Expense [Member] | Non Designated as Hedging Instrument [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount of gain (loss) included in income (expense)	0	0	0	(1)
Commodity Contract [Member] | Non Designated as Hedging Instrument [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount of gain (loss) included in income (expense)	478	937	1,610	2,703
Foreign Currency Derivative Contracts [Member] | Non Designated as Hedging Instrument [Member]
Other Non Interest Income Non Hedging Interest Rate Derivatives [Line Items]
Amount of gain (loss) included in income (expense)	$ 0	$ 0	$ 4	$ 55