Share-Based Compensation (Summary Of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
Feb. 28, 2018	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding Shares, Beginning balance (in shares)		99,500
Exercised, (in shares)		(22,000)
Canceled or expired, (in shares)	(10,000)	(10,000)
Outstanding Shares, Ending balance (in share)		67,500
Exercisable, (in shares)		15,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, Weighted-Average Exercise Price, Beginning balance (in dollars per share)		$ 42.77
Exercised, Weighted-Average Exercise Price (in dollars per share)		41.92
Canceled or Expired, Weighted-Average Exercise Price (in dollars per share)		43.01
Outstanding, Weighted-Average Exercise Price, Ending balance (in dollars per share)		43.01
Exercisable, Weighted-Average Exercise Price (in dollars per share)		$ 43.01
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, Weighted-Average Remaining Contractual Term (Years)		8 years 1 month 6 days
Exercisable, Weighted-Average Remaining Contractual Term (Years)		8 years 1 month 6 days
Outstanding, Aggregate Intrinsic Value		$ 376
Exercisable, Aggregate Intrinsic Value		$ 84

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

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