Share Options And Awards (Summary Of Option Activity) (Details) - $ / shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares under option, outstanding beginning of period (in shares)	207,416	279,877	828,354
Shares under option, forfeited or expired (in shares)	(23,222)	(1,136)	(196,159)
Shares under option, exercised (in shares)	(141,178)	(71,325)	(352,318)
Shares under option, outstanding end of period (in shares)	43,016	207,416	279,877
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, outstanding beginning of period (in dollars per share)	$ 23.84	$ 22.30	$ 23.58
Weighted average exercise price, forfeited or expired (in dollars per share)	22.68	11.85	32.22
Weighted average exercise price, exercised (in dollars per share)	23.72	17.98	19.78
Weighted average exercise price, outstanding end of period (in dollars per share)	$ 24.87	$ 23.84	$ 22.30

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Weighted average price of options that were either forfeited or expired.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Number of share options (or share units) exercised during the current period.

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