Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Aug. 31, 2014	Aug. 31, 2013
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 44,168	$ 54,557
Denominator:
Denominator for basic earnings per share attributable to controlling interest - weighted average common shares	67,567	69,601
Effect of dilutive securities	2,171	2,482
Denominator for diluted earnings per share attributable to controlling interest - adjusted weighted average common shares	69,738	72,083
Basic earnings per share attributable to controlling interest	$ 0.65	$ 0.78
Diluted earnings per share attributable to controlling interest	$ 0.63	$ 0.76