Share Repurchase Program (Schedule Of Shares Repurchased) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Proceeds from (Repurchase of) Equity [Abstract]
Shares repurchased	1,633	1,575	2,560	3,763
Average price per share	$ 366.76	$ 264.38	$ 359.63	$ 256.64
Total investment	$ 598,846	$ 416,402	$ 920,692	$ 965,830

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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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration