Stock-Based Compensation (Details 1) (USD $)	6 Months Ended
Aug. 31, 2013	Aug. 31, 2013
Award transactions on stock options
Outstanding, Beginning	1,362,373
Outstanding shares awards exercised	(269,423)
Outstanding shares awards canceled	(8,376)
Outstanding, Ending	1,084,574
Outstanding shares vested or expected to vest		1,084,574
Outstanding shares exercisable		934,403
Award transactions on stock options, Weighted Average Exercise Price [Roll Forward]
Weighted average exercise price, Beginning	$ 15.89
Weighted average exercise price, Awards exercised	$ 21.36
Weighted average exercise price, Awards canceled	$ 19.40
Weighted average exercise price, Ending	$ 14.52
Weighted average exercise price, Vested or expected to vest		$ 14.52
Weighted average exercise price, Exercisable		$ 15.51
Weighted average remaining contractual life, Outstanding	5 years 2 months 0 days
Weighted average remaining contractual life, Vested of expected to vest	5 years 2 months 0 days
Weighted average remaining contractual life, Exercisable	4 years 9 months 0 days
Aggregate intrinsic value, Outstanding		$ 14,524,796
Aggregate intrinsic value, Vested or expected to vest		14,524,796
Aggregate intrinsic value, Exercisable		$ 11,587,451

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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.

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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 vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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 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 remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options outstanding.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the 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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