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, 2016	Aug. 31, 2015
Balance as of May 31, 2016	$ 919,846
Net earnings	68,536	$ 34,995
Other comprehensive income (loss)	(40)	$ 2,445
Common shares issued, net of withholding tax	5,821
Common shares in NQ plans	634
Stock-based compensation	3,491
Cash dividends declared	(12,877)
Dividends to noncontrolling interest	(4,331)
Balance as of August 31, 2016	981,080
Additional Paid-in Capital
Balance as of May 31, 2016	298,984
Common shares issued, net of withholding tax	5,821
Common shares in NQ plans	634
Stock-based compensation	3,491
Balance as of August 31, 2016	308,930
Accumulated Other Comprehensive Loss, Net of Tax
Balance as of May 31, 2016	(28,565)
Other comprehensive income (loss)	(45)
Balance as of August 31, 2016	(28,610)
Retained Earnings
Balance as of May 31, 2016	522,952
Net earnings	65,567
Cash dividends declared	(12,877)
Balance as of August 31, 2016	575,642
Parent
Balance as of May 31, 2016	793,371
Net earnings	65,567
Other comprehensive income (loss)	(45)
Common shares issued, net of withholding tax	5,821
Common shares in NQ plans	634
Stock-based compensation	3,491
Cash dividends declared	(12,877)
Balance as of August 31, 2016	855,962
Noncontrolling Interest
Balance as of May 31, 2016	126,475
Net earnings	2,969
Other comprehensive income (loss)	5
Dividends to noncontrolling interest	(4,331)
Balance as of August 31, 2016	$ 125,118