Stock-based Compensation (Details1) (Stock Options [Member], USD $)	9 Months Ended
Sep. 30, 2012
Stock Options [Member]
Summary of stock option activity
Outstanding at December 31, 2011, Number of Shares	352,942
Exercised, Number of Shares	(87,463)
Forfeited, Number of Shares	(1,563)
Outstanding at September 30, 2012, Number of Shares	263,916
Outstanding at December 31, 2011, Weighted Average Exercise Price	$ 20.21
Exercised, Weighted Average Exercise Price	$ 20.43
Forfeited, Weighted Average Exercise Price	$ 28.58
Outstanding at September 30, 2012, Weighted Average Exercise Price	$ 20.09

Weighted average price of options that were either forfeited or expired.

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- Definition

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.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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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

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- Definition

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

+ References

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- Definition

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

+ References

No definition available.

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

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