Share-Based Compensation and Benefit Plans (Summary Of Share Incentive Plans) (Details) - $ / shares	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding Options, Beginning balance	68,978
Granted, Options Outstanding	9,994
Exercised/Vested, Options Outstanding	(78,972)
Forfeited, Options Outstanding	0
Outstanding Options, Ending balance	0	68,978
Weighted Average Exercise/Grant Price, Beginning balance	$ 61.15
Granted, Weighted Average Exercise/Grant Price	78.55
Exercised/Vested, Weighted Average Exercise/Grant Price	63.35
Forfeited, Weighted Average Exercise/Grant Price	0.00
Weighted Average Exercise/Grant Price, Ending balance	$ 0.00	$ 61.15
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested share awards outstanding, Beginning balance	499,898
Granted, Share Awards Outstanding	232,478
Exercised/Vested, Share Awards Outstanding	(316,668)
Forfeited, Share Awards Outstanding	(25,027)
Nonvested share awards outstanding, Ending balance	390,681	499,898
Nonvested share awards outstanding, Weighted Average Exercise/Grant Price Beginning	$ 75.80
Granted, Weighted Average Exercise/Grant Price	82.81	$ 83.41	$ 74.92
Exercised/Vested, Weighted Average Exercise/Grant Price	75.66
Forfeited, Weighted Average Exercise/Grant Price	79.83
Nonvested share awards outstanding, Weighted Average Exercise/Grant Price Ending	$ 79.82	$ 75.80

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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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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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

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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- Definition

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

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No definition available.

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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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- Definition

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

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No definition available.

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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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No definition available.

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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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No definition available.

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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