Loans and Allowance for Credit Losses - Modified Payment Status (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	$ 207	$ 632	$ 68
Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		632
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Residential real estate [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	207	632	68
Residential real estate [Member] | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		632
Residential real estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Residential real estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Residential real estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Residential real estate [Member] | Senior Lien
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	$ 207	632	$ 68
Residential real estate [Member] | Senior Lien | Financial Asset, Not Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		632
Residential real estate [Member] | Senior Lien | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Residential real estate [Member] | Senior Lien | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		0
Residential real estate [Member] | Senior Lien | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment		$ 0