Share Based Compensation (Schedule Of Share-based Compensation, Stock Options, Activity) (Details) - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option, Outstanding as of December 31,	1,546,014	1,639,865	1,690,899	1,546,508
Stock Options, Granted, Number of Shares	1,013,893
Stock Options, Exercised, Number of Shares	562,587	113,820	40,461
Stock Options, Forfeited, Number of Shares	3,374	18,760	0
Stock Options, Expired, Number of Shares	541,783	116,004	7,498
Stock Options Weighted Average Exercise Price Outstanding	$ 39.73	$ 63.09
Stock Options, Granted, Weighted Average Exercise Price	41.69
Stock Options, Exercised, Weighted Average Exercise Price	37.6
Stock Options, Forfeited, Weighted Average Exercise Price	40.90
Stock Options. Expired, Weighted Average Exercise Price	$ 47.04
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	1,031,581
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 39.32

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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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-Publisher FASB
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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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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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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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Gross 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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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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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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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

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