Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	Aug. 31, 2012
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 54,557	$ 33,962
Denominator:
Denominator for basic earnings per share attributable to controlling interest - weighted average common shares	69,601	68,278
Effect of dilutive securities	2,482	1,293
Denominator for diluted earnings per share attributable to controlling interest - adjusted weighted average common shares	72,083	69,571
Basic earnings per share attributable to controlling interest	$ 0.78	$ 0.50
Diluted earnings per share attributable to controlling interest	$ 0.76	$ 0.49