Employer Contributions, Participant Contributions and Benefit Payments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Plans
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	$ 4,100	$ 4,665	$ 6,916
Benefit Payments	6,489	6,038	6,877
Other Postretirement Benefit Plans, Defined Benefit
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	8,903	4,156	4,000
Participant Contributions	220	240	121
Benefit Payments	2,905	2,568	1,758
Supplemental Employee Retirement Plans, Defined Benefit
Defined Contribution Plan Disclosure [Line Items]
Employer Contributions	637	654	610
Benefit Payments	$ 637	$ 654	$ 610