Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Benefit Plan [Abstract]
Profit Sharing and Retirement Savings Plan, plan expense	$ 86.6	$ 181.4	$ 307.9
Unfunded obligation	28.2	27.0
Expense associated with early retiree medical plan	$ 2.5	$ 2.0	$ 2.1
Discount rate used to calculate benefit obligation	2.40%	3.23%	4.24%
Health care cost trend rate	5.70%	6.00%	6.30%
Projected ultimate future health care cost trend rate	4.50%
Year that trend rate is projected to reach ultimate rate	2037