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.

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), d(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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-Section 50

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- Definition

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.

+ 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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-Subparagraph (c)(1)(i)-(ii)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(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.

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- Definition

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.

+ 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)(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

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-Topic 718

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- Definition

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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Stock-Based Compensation (Additional Information Regarding Options Outstanding And Exercisable) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Shares	3,608	3,786	4,196	3,786
Outstanding, Weighted Average Contractual Life (in years)	4.10
Outstanding, Weighted Average Exercise Price	$ 28.06	$ 24.78	$ 21.77	$ 20.33
Exercisable, Shares	1,968
Exercisable, Weighted Average Exercise Price	$ 24.32
$0.00 - $5.25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Shares	102
Outstanding, Weighted Average Contractual Life (in years)	1.9
Outstanding, Weighted Average Exercise Price	$ 3.61
Exercisable, Shares	102
Exercisable, Weighted Average Exercise Price	$ 3.61
$5.26 - $10.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Shares	125
Outstanding, Weighted Average Contractual Life (in years)	3.0
Outstanding, Weighted Average Exercise Price	$ 8.54
Exercisable, Shares	125
Exercisable, Weighted Average Exercise Price	$ 8.54
$10.51 - $21.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Shares	1,107
Outstanding, Weighted Average Contractual Life (in years)	4.1
Outstanding, Weighted Average Exercise Price	$ 19.44
Exercisable, Shares	625
Exercisable, Weighted Average Exercise Price	$ 19.25
$21.01 - $31.50 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Shares	592
Outstanding, Weighted Average Contractual Life (in years)	3.0
Outstanding, Weighted Average Exercise Price	$ 28.25
Exercisable, Shares	543
Exercisable, Weighted Average Exercise Price	$ 28.32
$31.51 - $47.25 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding, Shares	1,682
Outstanding, Weighted Average Contractual Life (in years)	4.8
Outstanding, Weighted Average Exercise Price	$ 36.61
Exercisable, Shares	573
Exercisable, Weighted Average Exercise Price	$ 33.20