Loans - Non-Accrual Loans, Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	$ 71,515	$ 60,907
Non-accrual with no credit loss allowance	28,962	22,932
Commercial Portfolio Segment [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	25,446	19,545
Non-accrual with no credit loss allowance	6,119	5,391
Commercial and Industrial Total Energy Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	10,293	11,500
Non-accrual with no credit loss allowance	6,791	7,398
Commercial Real Estate Buildings Land And Other Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	30,012	22,420
Non-accrual with no credit loss allowance	12,519	4,983
Construction Loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	0	0
Non-accrual with no credit loss allowance	0	0
Total consumer real estate loans [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	5,764	7,442
Non-accrual with no credit loss allowance	3,533	5,160
Consumer Loan [Member]
Non Accrual Loans Segregated By Class Of Loans [Line Items]
Non-accrual loans	0	0
Non-accrual with no credit loss allowance	$ 0	$ 0