Summary of Significant Accounting Policies - Additional Information (Detail)		3 Months Ended								12 Months Ended
	Apr. 10, 2023	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) Bank	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jan. 01, 2023 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Period for federal funds sold outstanding										1 day
Accrued interest receivable										$ 10,200,000	$ 8,600,000
Delinquent loan is well secured and process of collection										90 days
Mortgage loans charged off days past due										180 days
Consumer and credit card loans to accrue interest charged off										120 days
Unrecognized interest income until loan balance reduced										$ 0
Maximum time for re-evaluation (in months)										12 months
Re-evaluation period for real estate										2 years
Amount of fair value of capital over carrying value			$ 8,800,000
Percentage of fair value of capital over carrying value			2.70%
Number of times fair value of capital in excess of carrying value of goodwill description										over 0.1 times
Foreclosed real estate										$ 0	0
Percentage of likelihood of realization of recognized tax benefit, minimum										50.00%
Provision for credit losses - loans		$ 278,000	$ 460,000	$ 143,000	$ 817,000	$ 755,000	$ 1,637,000	$ 1,628,000	$ 580,000	$ 1,698,000	4,600,000	$ 3,444,000
Number of peer group banks | Bank										307
Reserve portion of allowance of credit loss										$ 400,000	$ 2,000,000
Captives provision existence period	10 years
Commercial and Agricultural [member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of external and independent loan										35.00%
ASU 2016-13 [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]		true								true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2023								Jan. 01, 2023
Change in accounting principle, accounting standards update, immaterial effect [true false]		true								true
Current expected credit losses		$ 3,600,000								$ 3,600,000			$ 26,043,000
Tax impact portion of deferred tax asset		1,100,000								1,100,000
ASU 2016-13 [Member] | Letter of credit
Summary Of Significant Accounting Policies [Line Items]
Current expected credit losses		3,400,000								3,400,000
ASU 2016-13 [Member] | Unfunded loan commitment
Summary Of Significant Accounting Policies [Line Items]
Current expected credit losses		$ 900,000								$ 900,000
ASU 2022-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted [true false]		true								true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2023								Jan. 01, 2023
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Maturity period of cash equivalents										3 months
Asset value of peer group banks										$ 5,000,000,000
Percentage of captive claims listed transaction loss ratio	65.00%
Percentage of captive claims transaction of interest loss ratio	70.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Market Capitalization From Increased Bank Equities		$ 85,000,000
Increase in fair value estimate										$ 8,800,000