Benefit Plans (Summary Of Non-Qualified Stock Option Activity) (Details) (Non-Qualified Stock Options [Member], USD $)	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010
Non-Qualified Stock Options [Member]
Outstanding, Jan. 1, Shares	163,680	384,331
Exercised, Shares	(62,481)	(151,693)
Expired, Shares		(29,218)
Outstanding and exercisable, Sep. 30, Shares	101,199	203,420
Outstanding, Jan. 1, Weighted Average Fair Value	$ 24.51	$ 27.02
Exercised, Weighted Average Fair Value	$ 27.10	$ 28.34
Expired, Weighted Average Fair Value		$ 28.59
Outstanding and exercisable, Sep. 30, Weighted Average Fair Value	$ 22.92	$ 25.81

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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-Name Statement of Financial Accounting Standard (FAS)

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

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