Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), net of tax	$ (193,905)	$ 981
Net unrealized loss on available for sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), before tax	(290,549)	(392)
Tax effect	85,897	116
Accumulated other comprehensive income (loss), net of tax	(204,652)	(276)
Unfunded status of the supplemental retirement plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), before tax	13,901	2,399
Tax effect	(4,110)	(709)
Accumulated other comprehensive income (loss), net of tax	9,791	1,690
Joint beneficiary agreement liability, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), before tax	$ 956	$ (433)