Loans - Non-Accrual Loans, Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	$ 62,393	$ 78,866
Financing Receivable, Nonaccrual, No Allowance	25,369	32,885
Commercial Portfolio Segment [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	38,015	46,004
Financing Receivable, Nonaccrual, No Allowance	10,614	8,800
Commercial and Industrial Total Energy Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	4,020	4,079
Financing Receivable, Nonaccrual, No Allowance	1,343	1,377
Commercial Real Estate Buildings Land And Other Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	14,058	21,920
Financing Receivable, Nonaccrual, No Allowance	9,267	18,660
Construction Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Nonaccrual, No Allowance	0	0
Total consumer real estate loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	6,107	6,511
Financing Receivable, Nonaccrual, No Allowance	3,952	4,048
Consumer Loan [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Financing Receivable, Nonaccrual	193	352
Financing Receivable, Nonaccrual, No Allowance	$ 193	$ 0