Loans and the Allowance for Credit Losses - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Financing Receivable, Recorded Investment [Line Items]
Net deferred loan fee income (costs)	$ (10,300,000)		$ (9,600,000)
Un-accreted discount on purchased loans from acquisitions	16,700,000		18,000,000.0
Reserve on accrued interest related to CARES Act	200,000
Accrued interest receivable for loans	53,000,000.0
Accrued interest receivable for loans related to CARES Act	16,700,000
Aggregate amount of residential real estate, home equity and consumer loans classified as substandard	20,400,000		24,800,000
Internally assigned loan grades to residential real estate, home equity and consumer loans	2,600,000		5,900,000
Unfunded commercial loan commitments	30,300,000		25,000,000.0
TDRs defaulted		$ 0
Other real estate owned	1,475,000		1,397,000
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Other real estate owned	100,000		0
Foreclosure proceedings in process on residential real estate loans	5,300,000		$ 4,900,000
90 Days or More Past Due [Member]
Financing Receivable, Recorded Investment [Line Items]
Modifications loans	0
Commercial and Industrial [Member] | Maximum [Member]
Financing Receivable, Recorded Investment [Line Items]
Annual sales of borrowers	100,000,000
Unfunded Loan Commitment [Member]
Financing Receivable, Recorded Investment [Line Items]
Modifications loans	$ 2,800,000