Note 15. Income Taxes (Detail) (USD $)	3 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended
Nov. 30, 2011	Nov. 30, 2010	Aug. 31, 2011	May 31, 2011	Nov. 30, 2011 Estimated [Member]	May 31, 2011 Reenactment Of Federal R&D Credit [Member]	Nov. 30, 2011 Actual [Member]
Effective Income Tax Rate, Continuing Operations	32.10%	30.10%			32.10%		30.80%
Income Tax Expense (Benefit)	$ 21,486,000	$ 17,953,000				$ 1,400,000
Unrecognized Tax Benefits	7,526,000		7,204,000	7,500,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued				$ 1,000,000

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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- Definition

This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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