Loans (Non-Accrual Loans, Segregated by Class of Loans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	$ 70,482	$ 78,866
Financing Receivable, Nonaccrual, No Allowance	38,116	32,885
Commercial Portfolio Segment [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	50,659	46,004
Financing Receivable, Nonaccrual, No Allowance	26,693	8,800
Commercial and Industrial Total Energy Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	3,023	4,079
Financing Receivable, Nonaccrual, No Allowance	1,304	1,377
Commercial Real Estate Owner Occupied
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	7,581	17,643
Financing Receivable, Nonaccrual, No Allowance	4,782	16,395
Commercial Real Estate Non-Owner Occupied
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	465	2,144
Financing Receivable, Nonaccrual, No Allowance	465	2,144
Construction Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	1,874	2,133
Financing Receivable, Nonaccrual, No Allowance	202	121
Total consumer real estate loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	6,615	6,511
Financing Receivable, Nonaccrual, No Allowance	4,486	4,048
Consumer Loan [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	265	352
Financing Receivable, Nonaccrual, No Allowance	$ 184	$ 0