Capital Stock Repurchase Plan Transactions (Schedule Of Repurchased Capital Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Capital Stock Repurchase Plan Transactions [Abstract]
Total cost of repurchased shares	$ 121,882	$ 21,914	$ 166,649	$ 122,148
Shares repurchased	250,000	50,000	350,000	275,000
Weighted average price per share	$ 487.52	$ 438.27	$ 476.14	$ 444.18

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

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