Loans And Allowance For Credit Losses - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Accounts Notes And Loans Receivable [Line Items]
Loans held by subsidiaries subject to blanket liens	$ 5,449,122,000
Line of credit	0	$ 0
Nonaccrual, past due 90 days or more and still accruing, restructured loans and foreclosed assets	63,096,000	35,096,000
Nonaccrual loans	61,938,000	33,609,000
Interest income recognized on impaired loans	2,561,000	1,714,000	$ 1,607,000
Additional funds advanced in connection with impaired loans	0
Provision for loan losses	13,049,000	15,050,000
Reserve for unfunded commitments (Other liabilities)	8,677,000	7,903,000
Available line of credit	1,863,674,000
Undisbursed Commitments	1,046,500,000
Unfunded Loan Commitment [Member]
Accounts Notes And Loans Receivable [Line Items]
Provision for loan losses	13,049,000
Reversal of Provision for credit losses	$ 774,000	$ 4,419,000