Employee Benefit Plans (Disaggregated Information Related to Corporations Defined Benefit Pension Plans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 142,372	$ 143,944	$ 185,925	$ 197,593
Accumulated benefit obligation	142,372	143,944	185,925
Fair value of plan assets	174,611	161,823	197,747	$ 182,088
Funded status of the plan at end of year and accrued benefit (liability) recognized	32,239	17,879	$ 11,822
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	130,750	131,648
Accumulated benefit obligation	130,750	131,648
Fair value of plan assets	174,611	161,823
Funded status of the plan at end of year and accrued benefit (liability) recognized	43,861	30,175
Restoration Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	11,622	12,296
Accumulated benefit obligation	11,622	12,296
Fair value of plan assets	0	0
Funded status of the plan at end of year and accrued benefit (liability) recognized	$ (11,622)	$ (12,296)