Share-Based Compensation And Share Repurchase Plans (Summary Of Vested And Unvested Stock Options) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining years of contractual life, Vested	6 months 21 days	1 year 2 months 1 day	1 year 5 months 1 day
Weighted average remaining years of contractual life, Nonvested	1 year 9 months 14 days	1 year 2 months 26 days	2 years 3 months 14 days
Class A [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested	205,122	276,218	384,189
Weighted average exercise price, Vested	$ 15.92	$ 15.81	$ 15.38
Unvested	207,657	51,281	133,155
Weighted average exercise price, Nonvested	$ 4.54	$ 16.15	$ 15.65