Employer Contributions, Participant Contributions and Benefit Payments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Plans
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	$ 3,850	$ 3,800	$ 4,100
Benefits Paid	8,877	9,724	6,489
Other Postretirement Benefit Plans, Defined Benefit
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	2,790	12,153	8,903
Participant Contributions	234	279	220
Benefits Paid	2,767	3,503	2,905
Supplemental Employee Retirement Plans, Defined Benefit
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	665	637	637
Benefits Paid	$ 665	$ 637	$ 637