Equity-Based Compensation (Summary Of Outstanding And Exercisable Options) (Details) (USD $)	3 Months Ended
Mar. 31, 2012 Y
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	1,640,276
Number of Shares, Exercisable	1,538,022
Aggregate intrinsic value, Outstanding	$ 3,160,000
Weighted-average remaining contractual term, Outstanding (years)	4.1
Aggregate intrinsic value, Exercisable	2,785,000
Weighted-average remaining contractual term, Exercisable (years)	4.0
$ 1.29-$36.49 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	477,658
Weighted-Average Remaining Contractual Life, Outstanding (years)	4.91
Number of Shares, Exercisable	382,829
Weighted-Average Exercise Price, Exercisable	$ 31.67
Range of Exercise Prices, Minimum	$ 1.29
Range of Exercise Prices, Maximum	$ 36.49
Weighted-Average Exercise Price, Outstanding	$ 32.25
$ 36.80-$41.25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	384,646
Weighted-Average Remaining Contractual Life, Outstanding (years)	5.06
Number of Shares, Exercisable	377,221
Weighted-Average Exercise Price, Exercisable	$ 39.85
Range of Exercise Prices, Minimum	$ 36.80
Range of Exercise Prices, Maximum	$ 41.25
Weighted-Average Exercise Price, Outstanding	$ 39.80
$ 42.28-$45.62 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	401,316
Weighted-Average Remaining Contractual Life, Outstanding (years)	3.49
Number of Shares, Exercisable	401,316
Weighted-Average Exercise Price, Exercisable	$ 44.51
Range of Exercise Prices, Minimum	$ 42.28
Range of Exercise Prices, Maximum	$ 45.62
Weighted-Average Exercise Price, Outstanding	$ 44.51
$ 46.18-$51.62 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	374,856
Weighted-Average Remaining Contractual Life, Outstanding (years)	2.70
Number of Shares, Exercisable	374,856
Weighted-Average Exercise Price, Exercisable	$ 48.63
Range of Exercise Prices, Minimum	$ 46.18
Range of Exercise Prices, Maximum	$ 51.62
Weighted-Average Exercise Price, Outstanding	$ 48.63
$ 53.92-$53.92 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	1,800
Weighted-Average Remaining Contractual Life, Outstanding (years)	2.16
Number of Shares, Exercisable	1,800
Weighted-Average Exercise Price, Exercisable	$ 53.92
Range of Exercise Prices, Minimum	$ 53.92
Range of Exercise Prices, Maximum	$ 53.92
Weighted-Average Exercise Price, Outstanding	$ 53.92
Stock Option And Stock Appreciation Rights (SARs) [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of Shares, Outstanding	1,259,716
Number of Shares, Exercisable	293,246
Aggregate intrinsic value, Outstanding	13,133,000
Weighted-average remaining contractual term, Outstanding (years)	8.10
Aggregate intrinsic value, Exercisable	$ 4,498,000
Weighted-average remaining contractual term, Exercisable (years)	7.50

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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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.

+ References

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

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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.

+ References

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- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

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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.

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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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.

+ References

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The weighted-average period remaining as of the balance sheet date until option expiration pertaining to the outstanding stock options for all option plans in the customized range of exercise prices, which may be expressed in a variety of ways (for example, years, months).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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