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, 2020	Feb. 29, 2020	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	May 31, 2020	May 31, 2019	May 31, 2018
Numerator (basic & diluted):
Net earnings attributable to controlling interest - income available to common shareholders	$ 16,175	$ 15,311	$ 52,086	$ (4,776)	$ 37,738	$ 26,773	$ 34,002	$ 54,942	$ 78,796	$ 153,455	$ 194,794
Denominator:
Denominator for basic earnings per share attributable to controlling interest-weighted average common shares									54,958	57,196	60,923
Effect of dilutive securities									1,025	1,627	2,119
Denominator for diluted earnings per share attributable to controlling interest-adjusted weighted average common shares									55,983	58,823	63,042
Basic earnings per share attributable to controlling interest	$ 0.30	$ 0.28	$ 0.95	$ (0.09)	$ 0.68	$ 0.47	$ 0.59	$ 0.94	$ 1.43	$ 2.68	$ 3.20
Diluted earnings per share attributable to controlling interest	$ 0.29	$ 0.27	$ 0.93	$ (0.09)	$ 0.66	$ 0.46	$ 0.57	$ 0.91	$ 1.41	$ 2.61	$ 3.09