Employee Benefit Plans (Disaggregated Information Related to Corporations Defined Benefit Pension Plans) (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 185,925	$ 197,593	$ 186,641	$ 167,107
Accumulated benefit obligation	185,925	197,593	186,641
Fair value of plan assets	197,747	182,088	174,173	$ 152,820
Funded status of the plan at end of year and accrued benefit (liability) recognized	11,822	(15,505)	$ (12,468)
Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	170,389	180,986
Accumulated benefit obligation	170,389	180,986
Fair value of plan assets	197,747	182,088
Funded status of the plan at end of year and accrued benefit (liability) recognized	27,358	1,102
Restoration Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	15,536	16,607
Accumulated benefit obligation	15,536	16,607
Fair value of plan assets	0	0
Funded status of the plan at end of year and accrued benefit (liability) recognized	$ (15,536)	$ (16,607)