Capital Stock Transactions (Schedule Of Repurchased Capital Stock) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Capital Stock Transactions [Abstract]
Total cost of repurchased shares	$ 175,594	$ 92,631	$ 158,884
Shares repurchased	384,252	269,009	561,146
Weighted average price per share	$ 456.98	$ 344.34	$ 283.14

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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