Stock-Based Compensation (Details 1) (USD $)	3 Months Ended
Jun. 30, 2012
Stock option activity
Number of options, Beginning Balance	872,032
Number of options, Granted
Weighted average exercise price, Beginning Balance	$ 20.12
Weighted average exercise price, Granted
Number of options, Exercised
Weighted average exercise price, Exercised
Number of options, Cancelled	(17,074)
Weighted average exercise price, Cancelled	$ 13.22
Number of options, Ending Balance	854,985
Weighted average exercise price, Ending Balance	$ 20.26

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.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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-Subparagraph (c)(1)(iv)(3)

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

+ References

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

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