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Stock Option And Stock Award Plans (Summary Of Stock Options Outstanding) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Options
Number of Options, Outstanding, Beginning Balance	890,116	608,520	500,919
Number of Options, Granted	758,287	451,083	209,551
Number of Options, Forfeited and Expired	(10,000)	(96,089)	(60,685)
Number of Options, Exercised	(9,500)	(73,398)	(41,265)
Number of Options, Outstanding, Ending Balance	1,628,903	890,116	608,520
Weighted Average
Weighted Average Option Exercise Price/Share, Outstanding, Beginning Balance	$ 19.69	$ 19.75	$ 21.67
Weighted Average Option Exercise Price/Share, Granted	18.48	19.35	15.65
Weighted Average Option Exercise Price/Share, Forfeited and Expired	19.40	19.58	21.42
Weighted Average Option Exercise Price/Share, Exercised	19.40	18.15	19.84
Weighted Average Option Exercise Price/Share, Outstanding, Ending Balance	19.13	19.69	19.75
Minimum
Option Exercise Price/Share Range
Exercise Price, Outstanding, Beginning Balance	15.65	15.65	17.13
Exercise Price, Granted	18.48	19.35	15.65
Exercise Price, Forfeited and Expired	19.40	15.65	17.13
Exercise Price, Exercised	19.40	15.65	19.84
Exercise Price, Outstanding, Ending Balance	15.65	15.65	15.65
Maximum
Option Exercise Price/Share Range
Exercise Price, Outstanding, Beginning Balance	24.84	24.84	30.01
Exercise Price, Granted	18.48	19.35	15.65
Exercise Price, Forfeited and Expired	19.40	24.84	30.01
Exercise Price, Exercised	19.40	22.49	19.84
Exercise Price, Outstanding, Ending Balance	$ 24.84	$ 24.84	$ 24.84

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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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Net number of share options (or share units) granted during the period.

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

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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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