Loans and Allowance for Credit Losses - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2023 USD ($) Loan	Sep. 30, 2022 USD ($) Tdr	Sep. 30, 2023 USD ($) Loan	Sep. 30, 2022 USD ($) Tdr	Dec. 31, 2022 USD ($)
Financing Receivable Allowance For Credit Losses [Line Items]
Proceeds from sales of loans held for sale			$ 49,672,000	$ 33,657,000
Nonaccrual Loans	$ 17,042,000		17,042,000		$ 19,269,000
Restructured loans	3,200,000		3,200,000		5,200,000
Total Past Due	22,881,689,000		22,881,689,000		21,031,189,000
Non accrual loans with no related allowance for credit losses	14,576,000		14,576,000		16,704,000
Accrued interest on loans	115,700,000		$ 115,700,000		90,600,000
Number of reasonable and supportable forecast period			1 year
Commitments to lend to borrowers with loan modifications classified as TDR's		$ 0		0
Modifications made to borrowers experiencing financial difficulty commitment to lend	$ 0		$ 0
Loan modifications made to borrowers experiencing financial difficulty | Loan	0		0
Default payment of troubled restructuring		$ 0		0
Consumer Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Proceeds from sales of loans held for sale			$ 49,700,000	$ 33,700,000
Minimum [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Number of reasonable and supportable forecast period			1 year
Maximum [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Number of reasonable and supportable forecast period			3 years
Greater than 90 days Past Due and Accruing [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Total Past Due	$ 3,044,000		$ 3,044,000		$ 1,617,000
Consumer Real Estate Portfolio [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Number of Contracts | Tdr		0		2
Default payment of troubled restructuring, pre-modification				$ 5,100,000
Default payment of troubled restructuring, post-modification				$ 4,300,000