Summary of Changes in Total Equity, Shareholders' Equity Attributable to Controlling Interest, and Equity Attributable to Noncontrolling Interests (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2017	Aug. 31, 2016
Balance as of May 31, 2017	$ 1,073,929
Net earnings	48,074	$ 68,536
Other comprehensive income	17,753	$ (40)
Common shares issued, net of withholding tax	(3,274)
Common shares in NQ plans	536
Stock-based compensation	4,822
Purchases and retirement of common shares	(45,076)
Cash dividends declared	(13,317)
Dividends to noncontrolling interest	(720)
Balance as of August 31, 2017	1,082,727
Additional Paid-in Capital
Balance as of May 31, 2017	303,391
Common shares issued, net of withholding tax	(3,274)
Common shares in NQ plans	536
Stock-based compensation	4,822
Purchases and retirement of common shares	(4,235)
Balance as of August 31, 2017	301,240
Accumulated Other Comprehensive Loss, Net of Tax
Balance as of May 31, 2017	(27,775)
Other comprehensive income	17,314
Balance as of August 31, 2017	(10,461)
Retained Earnings
Balance as of May 31, 2017	676,019
Net earnings	45,534
Purchases and retirement of common shares	(40,841)
Cash dividends declared	(13,317)
Balance as of August 31, 2017	667,395
Parent
Balance as of May 31, 2017	951,635
Net earnings	45,534
Other comprehensive income	17,314
Common shares issued, net of withholding tax	(3,274)
Common shares in NQ plans	536
Stock-based compensation	4,822
Purchases and retirement of common shares	(45,076)
Cash dividends declared	(13,317)
Balance as of August 31, 2017	958,174
Noncontrolling Interest
Balance as of May 31, 2017	122,294
Net earnings	2,540
Other comprehensive income	439
Dividends to noncontrolling interest	(720)
Balance as of August 31, 2017	$ 124,553