Stock-Based Compensation Plans (Schedule Of Total Stock Option, Stock Award And PSU Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Granted	315,555	312,598	326,806
Weighted Average Grant-Date Price, Granted	$ 545.69	$ 496.25	$ 482.66
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Outstanding at January 1, 2020	1,181,154
Number of Options, Granted	315,555
Number of Options, Exercised/Vested	(370,105)
Number of Options, Canceled/Forfeited	(9,381)
Number of Options, Outstanding at December 31, 2020	1,117,223	1,181,154
Number of Options, Vested and expected to vest at December 31, 2020	1,117,223
Number of Options, Exercisable at December 31, 2020	494,064
Weighted Average Exercise Price, Outstanding at January 1, 2020	$ 432.75
Weighted Average Exercise Price, Granted	509.46
Weighted Average Exercise Price, Exercised/Vested	406.45
Weighted Average Exercise Price, Canceled/Forfeited	455.42
Weighted Average Exercise Price, Outstanding at December 31, 2020	462.94	$ 432.75
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2020	462.94
Weighted Average Exercise Price, Exercisable at December 31, 2020	$ 437.24
Weighted Average Remaining Contractual Life (Years), Outstanding at December 31, 2020	3 years 3 months 18 days
Weighted Average Remaining Contractual Life (Years), Vested and expected to vest at December 31, 2020	3 years 3 months 18 days
Weighted Average Remaining Contractual Life (Years), Exercisable at December 31, 2020	2 years 2 months 12 days
Aggregate Intrinsic Value, Outstanding at December 31, 2020	$ 134,531
Aggregate Intrinsic Value, Vested and expected to vest at December 31, 2020	134,531
Aggregate Intrinsic Value, Exercisable at December 31, 2020	$ 72,191
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Awards, Outstanding at January 1, 2020
Number of Awards, Granted	2,646
Number of Awards, Exercised/Vested	(2,646)
Number of Awards, Canceled/ Forfeited
Number of Awards, Outstanding at December 31, 2020
Number of Awards, Vested and expected to vest at December 31, 2020
Weighted Average Grant-Date Price, Outstanding at January 1, 2020
Weighted Average Grant-Date Price, Granted	545.69
Weighted Average Grant-Date Price, Exercised/Vested	545.69
Weighted Average Grant-Date Price, Canceled/Forfeited
Weighted Average Grant-Date Price, Outstanding at December 31, 2020
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2020
Performance Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Nonvested Target Units, Outstanding at January 1, 2020	37,490
Number of Nonvested Target Units, Granted	21,802
Number of Nonvested Target Units, Exercised/Vested	(15,138)
Number of Nonvested Target Units, Outstanding at December 31, 2020	44,154	37,490
Number of Nonvested Target Units, Vested and expected to vest at December 31, 2020	49,231
Weighted Average Grant-Date Price, Outstanding at January 1, 2020	$ 543.11
Weighted Average Grant-Date Price, Granted	557.23
Weighted Average Grant-Date Price, Exercised/Vested	544.36
Weighted Average Grant-Date Price, Outstanding at December 31, 2020	549.65	$ 543.11
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2020	$ 546.47