Stock-Based Compensation (Summary Of Stock Options) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of year, Weighted-Average Exercise Price	$ 62.80	$ 59.17	$ 56.37
Granted, Weighted-Average Exercise Price	0	0	0
Exercised, Weighted-Average Exercise Price	53.53	50.92	49.78
Forfeited, Weighted-Average Exercise Price	64.21	86.28	80.92
Outstanding, end of year, Weighted-Average Exercise Price	67.49	62.80	59.17
Vested and Exercisable, end of year, Weighted-Average Exercise Price	65.71	59.69	55.11
Nonvested, Weighted-Average Exercise Price	$ 94.77	$ 93.44	$ 91.71
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of year, Options	1,484	2,170	3,136
Granted, Options	0	0	0
Exercised, Options	(495)	(679)	(956)
Forfeited, Options	(5)	(7)	(10)
Outstanding, end of year, Options	984	1,484	2,170
Vested and Exercisable, end of year, Options	924	1,347	1,930
Nonvested, Options	60	137	240
Outstanding, Weighted-Average Remaining Contractual Term (in years)	3 years 2 months 4 days	3 years 6 months 18 days	4 years 1 month 6 days
Vested and Exercisable, Weighted-Average Remaining Contractual Term (in years)	2 years 11 months 12 days	3 years 1 month 20 days	3 years 6 months 25 days
Nonvested, Weighted-Average Remaining Contractual Term (in years)	6 years 8 months 15 days	7 years 7 months 6 days	8 years 3 months 18 days
Exercised, Aggregate Intrinsic Value	$ 72,098	$ 78,648	$ 58,472
Outstanding, Aggregate Intrinsic Value	186,926	118,908	191,895
Vested and Exercisable, Aggregate Intrinsic Value	177,111	112,133	178,456
Nonvested, Aggregate Intrinsic Value	9,815	6,775	13,439
Compensation Expense - Stock Options (in thousands)	$ 1,709	$ 2,006	$ 2,948