Share-Based Payments (Schedule Of Information Regarding Stock Options Outstanding) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Share-Based Payments [Abstract]
Options outstanding, Number	537	669
Options outstanding, weighted average per share exercise price	$ 37.98	$ 34.86
Options outstanding, aggregate intrinsic value	$ 11,039
Options outstanding, weighted average remaining contractual term (in years)	3 years 7 months 13 days
Options exercisable, Number	370
Options exercisable, weighted average per share exercise price	$ 33.09
Options exercisable, aggregate intrinsic value	$ 9,391
Options exercisable, weighted average remaining contractual term (in years)	1 year 7 months 24 days

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of options outstanding.

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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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