Share Based Compensation Plans (Details 1) (Stock Options Plan [Member], USD $)	12 Months Ended
Dec. 31, 2012
Stock Options Plan [Member]
Summary of transactions of the Company's stock option plans
Outstanding, Number of Options, Beginning balance	1,229,220
Granted at discount, Number of Options	75,932
Granted at market value, Number of Options	31,012
Exercised, Number of Options	(325,879)
Forfeited, Number of Options	(9,044)
Outstanding, Number of Options, Ending balance	1,001,241
Outstanding, Weighted Average Exercise Price, Beginning balance	$ 5.44
Granted at discount, Weighted Average Exercise Price	$ 0.00
Granted at market value, Weighted Average Exercise Price	$ 29.56
Exercised, Weighted Average Exercise Price	$ 3.80
Forfeited, Weighted Average Exercise Price	$ 10.00
Outstanding, Weighted Average Exercise Price, Ending balance	$ 6.27
Granted at discount, Weighted Average Fair Value	$ 21.98
Granted at market value, Weighted Average Fair Value	$ 16.70

Number of share options (or share units) granted during the period at discount.

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The weighted average grant-date fair value of options granted at discount during the reporting period as calculated by applying the disclosed option pricing methodology.

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

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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.

+ References

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

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

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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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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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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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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

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