Share-Based Compensation (Summary Of Nonvested Stock Activity) (Details) (USD $)	12 Months Ended
Dec. 31, 2011
Share-Based Compensation [Abstract]
Number of Awards, Outstanding at December 31, 2010	768,512
Number of Awards, Awarded - Employees	278,383
Number of Awards, Awarded - Directors	22,300
Number of Awards, Vested	(156,881)
Number of Awards, Forfeited	(47,781)
Number of Awards, Outstanding at December 31, 2011	864,533
Weighted- Average Grant-Date Fair Value, Outstanding at December 31, 2010	$ 27.93
Weighted- Average Grant-Date Fair Value, Awarded - Employees	$ 32.41
Weighted- Average Grant-Date Fair Value, Awarded - Directors	$ 38.11
Weighted- Average Grant-Date Fair Value, Vested	$ 37.78
Weighted- Average Grant-Date Fair Value, Forfeited	$ 25.15
Weighted- Average Grant-Date Fair Value, Outstanding at December 31, 2011	$ 28.00

Nonvested Stock Awarded To Directors

No definition available.

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- Definition

Non vested Stock Awarded To Directors, Weighted- Average Grant-Date Fair Value

+ References

No definition available.

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- Definition

Nonvested Stock Awarded To Employees

+ References

No definition available.

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- Definition

Non vested Stock Awarded To Employees, Weighted- Average Grant-Date Fair Value

+ References

No definition available.

+ Details

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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- Definition

The weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect during the reporting period as a result of the occurrence of a terminating event specified in the contractual agreement of the plan.

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding 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

-Subparagraph b(2)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(b)

-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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

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

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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