Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2023 USD ($) Branch Property Portfolio	Dec. 31, 2022 USD ($)	Dec. 31, 2020
Summary Of Significant Accounting Policies [Line Items]
Number of branches | Branch	192
Number of ATM | Property	183
Wholly-owned trust subsidiaries | Property	11
Held for sale securities, percentage of purchase price as condition for sale	15.00%
Allowance for credit losses, held-to-maturity debt securities	$ 192,000	$ 220,000
Non-accrual status period	90 days
Loans returned to accrual status, performance period	6 months
Number of categories of loan portfolio | Portfolio	3
Indefinite - lived intangible assets	$ 0
Period of interest rate lock commitments	60 days
ASU 2022-02 Financial Instruments - Credit Losses (Topic 326)
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2023
ASU 2023-05 - Business Combinations-Joint Venture Formations (Subtopic 805-60): Recognition and Initial Measurement
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2025
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	false
ASU 2022-04 - Liabilities Supplier Finance Programs (Sub-topic 405-50)
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	false
ASU 2023-02 Investments Equity Method and Joint Ventures (Topic 323)
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	false
ASU 2023-01 Leases (Topic 842): Common Control Arrangements
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	false
ASU 2022-03 Fair Value Measurement (Topic 820)
Summary Of Significant Accounting Policies [Line Items]
Change in Accounting Principle, Accounting Standards Update, Adopted [true false]	true
Change in Accounting Principle, Accounting Standards Update, Adoption Date	Jan. 01, 2024
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false]	false
Land Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life	15 years
Mortgage-Backed Securities and Collateralized Mortgage Obligations of Government Sponsored Entities and Agencies [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses, held-to-maturity debt securities	$ 0
Consumer Loan [Member]
Summary Of Significant Accounting Policies [Line Items]
Period of closed end loans loans charged down to net realizable value	120 days
Home Equity [Member]
Summary Of Significant Accounting Policies [Line Items]
Period of closed end loans loans charged down to net realizable value	180 days
Residential Real Estate Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Period of closed end loans loans charged down to net realizable value	180 days
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of voting interest			50.00%
Forecast period to measure expected credit losses on loan portfolio	1 year
Weighted-average estimated useful lives	10 years
Non-compete agreements, amortization period	1 year
Minimum [Member] | Furniture and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life	3 years
Minimum [Member] | Building and Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life	15 years
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Forecast period to measure expected credit losses on loan portfolio	2 years
Model reversion period to measure expected credit losses on loan portfolio	3 years
Weighted-average estimated useful lives	16 years
Non-compete agreements, amortization period	4 years
Maximum [Member] | Furniture and Equipment [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life	10 years
Maximum [Member] | Building and Building Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, Useful life	39 years
Maximum [Member] | CARES Act, Paycheck Protection Program [Member]
Summary Of Significant Accounting Policies [Line Items]
Loans receivable, threshold period past due	30 days