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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Capital Stock Repurchase Plan Transactions [Abstract]
Total cost of repurchased shares	$ 21,914	$ 22,676	$ 122,148	$ 71,926
Shares repurchased	50,000	69,009	275,000	219,009
Weighted average price per share	$ 438.27	$ 328.59	$ 444.18	$ 328.41

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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