Loans And Allowance For Credit Losses - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Loans held by subsidiaries subject to blanket liens	$ 4,154,241,000
Line of credit	0	$ 0
Nonaccrual, past due 90 days or more and still accruing, restructured loans and foreclosed assets	24,325,000	34,158,000
Nonaccrual loans	24,306,000	31,652,000
Interest income recognized on impaired loans	1,607,000	2,122,000	$ 1,006,000
Additional funds advanced in connection with impaired loans	0
Unfunded loan commitments	12,323,000
Provision for loan losses	$ 11,540,000	(2,089,000)
Default for purposes of this disclosure is a troubled debt restructured loan	90 days
Commitments to lend additional funds to borrowers with loan that have been modified as TDRs	$ 0
Total Loans	6,441,868,000	5,388,972,000
Reserve for unfunded commitments (Other liabilities)	12,323,000	6,436,000
Reversal of Provision for credit losses		2,089,000
Available line of credit	2,341,985,000
Federal Home Loan Bank Borrowings [Member]
Accounts Notes And Loans Receivable [Line Items]
Line of credit	0
Residentials Real Estate [Member]
Accounts Notes And Loans Receivable [Line Items]
Total Loans	459,000
Unfunded Loan Commitment [Member]
Accounts Notes And Loans Receivable [Line Items]
Unfunded loan commitments	$ 5,887,000	$ 950,000