Earnings Per Share (Schedule Of Computation Of Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share[Abstract]
Earnings	$ 205,544	$ 98,177	$ 108,743
Dilutive stock options, Income
Nonvested stock awards, Income
Diluted Earnings	$ 205,544	$ 98,177	$ 108,743
Earnings, Shares	16,059	16,057	16,383
Dilutive stock options, Shares	650	596	296
Nonvested stock awards, Shares	94	89	110
Diluted Earnings, Shares	16,803	16,742	16,789
Earnings per Share, Earnings	$ 12.80	$ 6.11	$ 6.64
Earnings per Share, Diluted earnings	$ 12.23	$ 5.86	$ 6.48

Amount of dilutive securities, nonvested stock awards

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Amount of dilutive securities stock options

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Number of additional shares included in diluted EPS for potentially dilutive effect of nonvested equity-based payment award containing forfeitable rights to dividends or dividend equivalents, whether paid or unpaid.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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