Derivative Financial Instruments - Schedule of Derivative Financial Instruments on Statements of Income (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Derivative [Line Items]
Derivatives in hedging relationships	$ 2,298	$ 2,949	$ 6,634	$ 7,421
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivatives in hedging relationships	2,022	2,470	6,060	7,384
Designated as Hedging Instrument [Member] \| Interest And Fees On Loans [Member] \| Interest Rate Contracts [Member] \| Fair Value Hedging [Member]
Derivative [Line Items]
Derivatives in hedging relationships	4	0	7	(3)
Designated as Hedging Instrument [Member] \| Interest on long-term borrowings [Member] \| Interest Rate Contracts [Member] \| Cash Flow Hedging [Member]
Derivative [Line Items]
Derivatives in hedging relationships	2,018	2,470	6,053	7,387
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	276	479	574	37
Not Designated as Hedging Instrument [Member] \| Income from Mortgage Banking Activities [Member] \| TBA Mortgage Backed Securities [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	665	659	657	(182)
Not Designated as Hedging Instrument [Member] \| Income from Mortgage Banking Activities [Member] \| Interest Rate Lock Commitments [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	(403)	(137)	(82)	198
Not Designated as Hedging Instrument [Member] \| Income from Mortgage Banking Activities [Member] \| Forward Loan Sale Commitments [Member]
Derivative [Line Items]
Derivatives not designated as hedging instruments	$ 14	$ (43)	$ (1)	$ 21