Employee Benefits - Additional information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 63,000	$ 59,000	$ 176,000	$ 163,000
Deferred Compensation Liability Current and Noncurrent	2,365,000		2,365,000		$ 2,071,000
Salary Continuation Plan [Member] | Supplemental Employee Retirement Plan [Member]
Liability, Defined Benefit Plan	$ 804,000		$ 804,000		735,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	5.00%		5.00%
Employee salary incremental percent			3.00%
Defined Contribution Plan, Cost	$ 37,000	32,000	$ 110,000	99,000
Deferred Directors Supplemental Retirement Plan [Member] | Supplemental Employee Retirement Plan [Member]
Pension Cost (Reversal of Cost)	14,000	$ 19,000	44,000	$ 57,000
Liability, Defined Benefit Plan	$ 596,000		$ 596,000		$ 581,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	6.25%		6.25%		6.25%
Defined Contribution Plan, Cost			$ 20,000
Previous final base fee, percentage			70.00%
Revised fixed annual retirement benefits, payable			$ 200,000
Deferred Compensation Liability Current and Noncurrent	$ 929,000		$ 929,000		$ 718,000