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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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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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A brief description of status of the tax examination, significant findings to date, and the entity's position with respect to the findings.

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The amount the liability recorded for the income tax examination increased or decreased in the current year/accounting period.

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Interest income derived from tax advantaged investment securities. Tax advantaged investment securities generally are, by statute, tax-reduced, tax-deferred, or tax-free. For example, interest earned by retirement plans and many state or municipal bonds which are exempt from certain taxes are considered tax advantaged or tax favored.

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Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011	Nov. 30, 2011
Income Taxes [Line Items]
Interest and penalties	$ 0	$ 0		$ 1,396
Effective tax rate	38.70%	35.60%	36.30%
Derecognition of expense recognized in income tax provision	1,396
Tax advantaged investments reduced tax expense	0	0	2
Valuation allowance	1,110	871
Undistributed earnings of foreign subsidiaries	$ 1,833	$ 1,599	$ 1,425
United States federal jurisdiction
Income Taxes [Line Items]
Jurisdiction	Years through fiscal 2009
State jurisdictions
Income Taxes [Line Items]
Jurisdiction	Through fiscal 2004 and 2005