Share Repurchase Program (Schedule Of Shares Repurchased) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Proceeds from (Repurchase of) Equity [Abstract]
Shares repurchased	1,025	932	3,585	4,695
Average price per share	$ 377.85	$ 306.22	$ 364.84	$ 266.48
Total investment	$ 387,255	$ 285,183	$ 1,307,947	$ 1,251,013

Number of shares that have been repurchased and retired during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration