Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2014	Feb. 28, 2013	Feb. 28, 2014	Feb. 28, 2013
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 40,603	$ 37,131	$ 118,137	$ 102,919
Denominator:
Denominator for basic earnings per share attributable to controlling interest - weighted average common shares	68,895	69,791	69,268	68,998
Effect of dilutive securities	2,633	2,123	2,642	1,503
Denominator for diluted earnings per share attributable to controlling interest - adjusted weighted average common shares	71,528	71,914	71,910	70,501
Basic earnings per share attributable to controlling interest	$ 0.59	$ 0.53	$ 1.71	$ 1.49
Diluted earnings per share attributable to controlling interest	$ 0.57	$ 0.52	$ 1.64	$ 1.46