Retirement Plans - Assumptions Used in Accounting for Plans (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Discount rate used to calculate benefit obligation	2.74%	2.40%	2.82%
Discount rate used to calculate net periodic pension cost	2.40%	2.82%	3.96%
Executive Compensation
Defined Benefit Plan Disclosure [Line Items]
Average annual increase in compensation	3.25%	3.25%	3.25%
Director Compensation
Defined Benefit Plan Disclosure [Line Items]
Average annual increase in compensation	0.00%	0.00%	0.00%