Retirement Plans (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Aug. 31, 2021	Dec. 31, 2020
Defined Contribution Plan Disclosure [Line Items]
Deferred compensation plan	$ 88,965,000	$ 50,000	$ 89,327,000	$ (115,000)
Accruals and other current liabilities	317,271,000		317,271,000			$ 226,793,000
Deferred compensation plan liabilities	89,174,000		89,174,000			2,422,000
Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits
Defined Contribution Plan Disclosure [Line Items]
Accruals and other current liabilities	7,306,000		7,306,000			169,000
Deferred compensation plan liabilities	89,174,000		89,174,000			2,422,000
Total DCP liabilities	96,480,000		96,480,000			$ 2,591,000
Nonqualified Plan | Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits
Defined Contribution Plan Disclosure [Line Items]
Deferred compensation plan	88,965,000	50,000	89,327,000	(115,000)
DCP participant deferrals	527,000	804,000	2,020,000	2,602,000
Contributions by employer	0	$ 0	0	$ 0
Nonqualified Plan | Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits | DCP, One-Time Inducement
Defined Contribution Plan Disclosure [Line Items]
Reclassified cumulative compensation cost	4,739,000		4,739,000
Deferred compensation plan	90,721,000		90,721,000
Deferred compensation liability	$ 95,460,000		$ 95,460,000
Nonqualified Plan | Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits | Class B Common Stock
Defined Contribution Plan Disclosure [Line Items]
Phantom shares, maximum elections (in shares)					1,500,000
Reduction in shares outstanding, basic (in shares)					1,500,000
Reduction in shares outstanding, diluted (in shares)					1,500,000
Phantom shares issuable (in shares)	25,503,049		25,503,049			30,590,955