Changes in Equity - Summary of Changes in Equity by Component and in Total (Detail) - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2018	Aug. 31, 2017
Balance at May 31, 2018	$ 1,036,375
Net earnings	56,958	$ 48,074
Other comprehensive loss	(5,762)	$ 17,753
Common shares issued, net of withholding tax	(4,091)
Common shares in NQ plans	152
Stock-based compensation	4,838
Purchases and retirement of common shares	(36,852)
Cash dividends declared	(13,668)
Dividends to noncontrolling interest	(2,320)
Balance at August 31, 2018	1,037,374
Accounting Standards Update 2014-09
ASC 606 transition adjustment	1,744
Additional Paid-in Capital
Balance at May 31, 2018	295,592
Common shares issued, net of withholding tax	(4,091)
Common shares in NQ plans	152
Stock-based compensation	4,838
Purchases and retirement of common shares	(4,003)
Balance at August 31, 2018	292,488
AOCI Attributable to Parent
Balance at May 31, 2018	(14,580)
Other comprehensive loss	(5,745)
Balance at August 31, 2018	(20,325)
Retained Earnings
Balance at May 31, 2018	637,757
Net earnings	54,942
Purchases and retirement of common shares	(32,849)
Cash dividends declared	(13,668)
Balance at August 31, 2018	647,356
Retained Earnings | Accounting Standards Update 2014-09
ASC 606 transition adjustment	1,174
Parent
Balance at May 31, 2018	918,769
Net earnings	54,942
Other comprehensive loss	(5,745)
Common shares issued, net of withholding tax	(4,091)
Common shares in NQ plans	152
Stock-based compensation	4,838
Purchases and retirement of common shares	(36,852)
Cash dividends declared	(13,668)
Balance at August 31, 2018	919,519
Parent | Accounting Standards Update 2014-09
ASC 606 transition adjustment	1,174
Noncontrolling Interest
Balance at May 31, 2018	117,606
Net earnings	2,016
Other comprehensive loss	(17)
Dividends to noncontrolling interest	(2,320)
Balance at August 31, 2018	117,855
Noncontrolling Interest | Accounting Standards Update 2014-09
ASC 606 transition adjustment	$ 570