Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Nov. 30, 2013	Nov. 30, 2012	Nov. 30, 2013	Nov. 30, 2012
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 22,977	$ 31,826	$ 77,534	$ 65,788
Denominator:
Denominator for basic earnings per share attributable to controlling interest - weighted average common shares	69,304	68,934	69,454	68,604
Effect of dilutive securities	2,522	1,477	2,635	1,230
Denominator for diluted earnings per share attributable to controlling interest - adjusted weighted average common shares	71,826	70,411	72,089	69,834
Basic earnings per share attributable to controlling interest	$ 0.33	$ 0.46	$ 1.12	$ 0.96
Diluted earnings per share attributable to controlling interest	$ 0.32	$ 0.45	$ 1.08	$ 0.94