Loans and the Allowance for Credit Losses - Recorded Investment in Non-Accrual Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Impaired [Line Items]
Non-accrual loans	$ 29,878	$ 38,185
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	2,138	2,946
Home Equity [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	5,322	5,044
Commercial Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	11,289	16,366
Commercial Real Estate [Member] | Commercial Real Estate - Land and Construction [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans		112
Commercial Real Estate [Member] | Commercial Real Estate - Improved Property [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	11,289	16,254
Residential Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	11,013	13,695
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Non-accrual loans	$ 116	$ 134