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, 2015	Aug. 31, 2014
Beginning Balance	$ 840,049
Net earnings	34,437	$ 48,820
Other comprehensive income (loss)	2,445	$ (8,631)
Common shares issued, net of withholding tax	(602)
Common shares in NQ plans	550
Stock-based compensation	5,965
Purchases and retirement of common shares	(27,582)
Cash dividends declared	(11,470)
Payments to noncontrolling interest	(4,901)
Ending Balance	838,891
Additional Paid-in Capital
Beginning Balance	289,078
Common shares issued, net of withholding tax	(602)
Common shares in NQ plans	550
Stock-based compensation	5,965
Purchases and retirement of common shares	(4,680)
Ending Balance	290,311
Cumulative Other Comprehensive Income (Loss), Net of Tax
Beginning Balance	(50,704)
Other comprehensive income (loss)	2,501
Ending Balance	(48,203)
Retained Earnings
Beginning Balance	510,738
Net earnings	31,410
Purchases and retirement of common shares	(22,902)
Cash dividends declared	(11,470)
Ending Balance	507,776
Parent
Beginning Balance	749,112
Net earnings	31,410
Other comprehensive income (loss)	2,501
Common shares issued, net of withholding tax	(602)
Common shares in NQ plans	550
Stock-based compensation	5,965
Purchases and retirement of common shares	(27,582)
Cash dividends declared	(11,470)
Ending Balance	749,884
Noncontrolling Interest
Beginning Balance	90,937
Net earnings	3,027
Other comprehensive income (loss)	(56)
Payments to noncontrolling interest	(4,901)
Ending Balance	$ 89,007