Computation of Basic and Diluted Earnings per Share Attributable to Controlling Interest (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	6 Months Ended
Nov. 30, 2014	Nov. 30, 2013	Nov. 30, 2014	Nov. 30, 2013
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 29,462us-gaap_NetIncomeLoss	$ 22,977us-gaap_NetIncomeLoss	$ 73,630us-gaap_NetIncomeLoss	$ 77,534us-gaap_NetIncomeLoss
Denominator:
Denominator for basic earnings per share attributable to controlling interest - weighted average common shares	67,105	69,304	67,337	69,454
Effect of dilutive securities	2,076	2,522	2,443	2,635
Denominator for diluted earnings per share attributable to controlling interest - adjusted weighted average common shares	69,181	71,826	69,780	72,089
Basic earnings per share attributable to controlling interest	$ 0.44us-gaap_EarningsPerShareBasic	$ 0.33us-gaap_EarningsPerShareBasic	$ 1.09us-gaap_EarningsPerShareBasic	$ 1.12us-gaap_EarningsPerShareBasic
Diluted earnings per share attributable to controlling interest	$ 0.43us-gaap_EarningsPerShareDiluted	$ 0.32us-gaap_EarningsPerShareDiluted	$ 1.06us-gaap_EarningsPerShareDiluted	$ 1.08us-gaap_EarningsPerShareDiluted

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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