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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.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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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

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- Definition

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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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

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- Definition

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

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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No definition available.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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No definition available.

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Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

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No definition available.

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

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

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-Name Accounting Standards Codification

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Share Based Compensation - Option Rollforward (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Exercised	(841,000)	(256,000)	(315,000)
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Exercise Price - Outstanding January 1, 2012	33.37
Weighted Average Exercise Price - Granted	34.77
Weighted Average Exercise Price - Exercised	27.21
Weighted Average Exercise Price - Expired	31.33
Weighted Average Exercise Price - Outstanding December 31, 2012	35.50
Exercisable at December 31, 2012	1,974,000
Weighted Average Exercise Price - Exercisable at December 31, 2012	36.14
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding January 1, 2012	3,311,000
Granted	257,000
Exercised	(841,000)
Forfeited	(65,000)
Outstanding December 31, 2012	2,662,000