Share-Based Compensation (Summary Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Share-Based Compensation [Abstract]
Outstanding Shares, Beginning balance	615,676
Granted, Shares	0
Exercised, Shares	(52,950)
Cancelled or expired, Shares	(18,501)
Outstanding Shares, Ending balance	544,225
Exercisable, Shares	408,824
Outstanding, Weighted-Average Exercise Price, Beginning balance	$ 45.06
Granted, Weighted-Average Exercise Price	$ 0.00
Exercised, Weighted-Average Exercise Price	$ 36.84
Cancelled or expired, Weighted-Average Exercise Price	$ 0.00
Outstanding, Weighted-Average Exercise Price, Ending balance	$ 46.09
Exercisable, Weighted-Average Exercise Price	$ 48.45
Outstanding, Weighted-Average Remaining Contractual Term (Years)	5.2
Exercisable, Weighted-Average Remaining Contractual Term (Years)	4.7
Outstanding, Aggregate Intrinsic Value	$ 2,057
Exercisable, Aggregate Intrinsic Value	$ 972

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of vested portions of options outstanding and currently exercisable under the option plan as of the balance sheet date.

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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 weighted average period between the balance sheet date and expiration for all vested portions of options outstanding and currently exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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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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The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

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

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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 stock options awarded under the plan during the reporting period.

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance sheet date.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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The weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

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

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