Loans and Allowance for Credit Losses - Summary of the Modifications Which Occurred During the Periods and the Change in the Recorded Investment Subsequent to the Modifications Occurring (Detail) $ in Thousands	3 Months Ended		9 Months Ended				12 Months Ended
	Sep. 30, 2022 USD ($) contract	Sep. 30, 2021 USD ($) contract	Sep. 30, 2022 loan	Sep. 30, 2022 contract	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($) contract	Dec. 31, 2021 loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	21	2	255	38		4	249
Pre- Modification Outstanding Recorded Investment	$ 5,687	$ 200			$ 9,636	$ 957
Post-Modification Modification Outstanding Recorded Investment	$ 5,687	$ 200			9,644	$ 957
Commercial and industrial | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	3		12	4			7
Pre- Modification Outstanding Recorded Investment	$ 2,997				5,415
Post-Modification Modification Outstanding Recorded Investment	$ 2,997				5,415
Business banking | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	9	0	27	20		1	8
Pre- Modification Outstanding Recorded Investment	$ 284	$ 0			854	$ 462
Post-Modification Modification Outstanding Recorded Investment	$ 284	$ 0			862	$ 462
Residential real estate | Residential Real Estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	5	0	143	8		1	148
Pre- Modification Outstanding Recorded Investment	$ 1,170	$ 0			1,899	$ 295
Post-Modification Modification Outstanding Recorded Investment	$ 1,170	$ 0			1,899	$ 295
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	4	2	71	6		2	83
Pre- Modification Outstanding Recorded Investment	$ 1,236	$ 200			1,468	$ 200
Post-Modification Modification Outstanding Recorded Investment	$ 1,236	$ 200			$ 1,468	$ 200