Stock Option Plan and Stock Based Compensation - Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
May 31, 2019	May 31, 2018	Feb. 28, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Options Outstanding, Beginning Balance	61,590
Number of Shares, Granted	0	0
Number of Shares, Exercised	(61,590)
Number of Shares, Options Outstanding, Ending Balance	0		61,590
Weighted Average Exercise Price, Beginning Balance	$ 15.88
Weighted Average Exercise Price, Exercised	$ 15.88
Weighted Average Exercise Price, Ending Balance			$ 15.88
Weighted Average Remaining Contractual Life (in years)			1 year 9 months 18 days
Aggregate Intrinsic Value			$ 327

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

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Number of options outstanding, including both vested and non-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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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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

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