Loans and Allowance for Loan 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				12 Months Ended
	Mar. 31, 2022 loan	Mar. 31, 2022 contract	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($) contract	Dec. 31, 2021 loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	250	7		1	249
Pre- Modification Outstanding Recorded Investment			$ 784	$ 295
Post-Modification Modification Outstanding Recorded Investment			792	$ 295
Business Banking | Commercial Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	13	5		0	8
Pre- Modification Outstanding Recorded Investment			440	$ 0
Post-Modification Modification Outstanding Recorded Investment			448	$ 0
Residential real estate | Residential Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	145	1		1	148
Pre- Modification Outstanding Recorded Investment			134	$ 295
Post-Modification Modification Outstanding Recorded Investment			134	$ 295
Consumer home equity | Consumer Portfolio Segment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts	81	1		0	83
Pre- Modification Outstanding Recorded Investment			210	$ 0
Post-Modification Modification Outstanding Recorded Investment			$ 210	$ 0