Summary of Significant Accounting Policies (Schedule of Stock by Class) (Details) - shares		12 Months Ended
	Oct. 21, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Class A  Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance (in shares)		30,892,000	29,975,000	44,078,000
Share repurchases	(10,800,000)	0	0	(14,785,000)
Employee and non-employee director stock transactions		633,000	917,000	682,000
Ending Balance (in shares)		31,525,000	30,892,000	29,975,000
Class B  Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance (in shares)		11,484,000	11,484,000	11,484,000
Share repurchases				0
Employee and non-employee director stock transactions		0	0	0
Ending Balance (in shares)		11,484,000	11,484,000	11,484,000