Stock-based Compensation Plans - Additional Information 4 (Detail) - USD ($) shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation plan vesting period			3 years
Deferred compensation plan	$ 35,462,000	$ 12,587,000	$ 55,273,000	$ 4,050,000
Shares held in rabbi trust total	6.5		6.5		6.1
Vested shares held in rabbi trust	5.0		5.0		5.0
Post-Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Estimated prior service cost amortized from accumulated other comprehensive income into general and administrative expense	$ 90,000	$ 90,000	$ 185,000	$ 185,000