Stock-Based Compensation (Summary Of Option Activity) (Details) (USD $)	3 Months Ended
Mar. 31, 2012 Y
Stock-Based Compensation [Abstract]
Outstanding, Shares, Beginning Balance	1,352,644
Expired, Shares	(849)
Exercised, Shares	(241,078)
Outstanding, Shares, Ending Balance	1,110,717
Outstanding, Weighted Average Exercise Price, Beginning Balance	$ 30.26
Expired, Weighted Average Exercise Price	$ 19.61
Exercised, Weighted Average Exercise Price	$ 26.22
Outstanding, Weighted Average Exercise Price, Ending Balance	$ 31.15
Outstanding, Weighted Average Remaining Contractual Term (in years)	2.0
Outstanding, Aggregate Intrinsic Value, Ending Balance	$ 10,412

Share Based Compensation Arrangements By Share Based Payment Award Options Outstanding Aggregate Intrinsic Value

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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.

+ References

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- Definition

The decrease in the number of shares that could be issued attributable to the lapse of rights to exercise previously issued stock options under the terms of the option agreements under the plan during the reporting period.

+ References

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The weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that lapsed during the reporting period.

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- Definition

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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