Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	May 31, 2019	May 31, 2018	May 31, 2017
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 37,738	$ 26,773	$ 34,002	$ 54,942	$ 30,769	$ 79,087	$ 39,403	$ 45,534	$ 153,455	$ 194,794	$ 204,515
Denominator:
Denominator for basic earnings per share attributable to controlling interest-weighted average common shares									57,196	60,923	62,443
Effect of dilutive securities									1,627	2,119	2,431
Denominator for diluted earnings per share attributable to controlling interest-adjusted weighted average common shares									58,823	63,042	64,874
Basic earnings per share attributable to controlling interest	$ 0.68	$ 0.47	$ 0.59	$ 0.94	$ 0.52	$ 1.31	$ 0.64	$ 0.73	$ 2.68	$ 3.20	$ 3.28
Diluted earnings per share attributable to controlling interest	$ 0.66	$ 0.46	$ 0.57	$ 0.91	$ 0.50	$ 1.27	$ 0.62	$ 0.70	$ 2.61	$ 3.09	$ 3.15