Stock-Based Compensation (Details 1) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation [Abstract]
Weighted-Average Exercise Price, Options Outstanding	$ 17.67	$ 16.31
Weighted-Average Exercise Price, Options Granted	$ 20.69
Weighted-Average Exercise Price, Options Exercised	$ 15.20
Weighted-Average Exercise Price, Options Forfeited	$ 17.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options Outstanding	4,215,811
Granted	379,900
Exercised	(1,836,572)
Forfeited	(121,836)
Options Outstanding	2,637,303

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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

+ References

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

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

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No definition available.

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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 stock options awarded under the plan during the reporting period.

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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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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.

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

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