Stock-Based Compensation - Summary Of Status Of Bank Stock Option Activity (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Balance at January 1	330,650	407,650
Granted	0	0
Exercised	(50,900)	(76,900)
Forfeited	0	0
Expired	0	(100)
Balance at December 31	279,750	330,650
Exercisable at December 31	279,750	330,650
Balance at January 1	$ 21.45	$ 20.08
Granted	0	0
Exercised	13.87	14.18
Forfeited	0	0
Expired	0	13.75
Balance at December 31	22.83	21.45
Exercisable at December 31	$ 22.83	$ 21.45
Balance at December 31	2 years 3 months	2 years 10 months 13 days
Exercisable at December 31	2 years 3 months	2 years 10 months 13 days
Balance at December 31	$ 3,654,453,000	$ 3,463,695
Exercisable at December 31	$ 3,654,453,000	$ 3,463,695,000