Schedule of Gain (Loss) Recognized in Earnings for Economic (Non-Designated) Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 30, 2016	Nov. 30, 2015	Nov. 30, 2016	Nov. 30, 2015
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ 1,404	$ (5,320)	$ 4,246	$ (8,075)
Commodity Contracts | Cost of Goods Sold
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	2,003	(5,390)	4,911	(8,145)
Foreign Currency Contracts | Miscellaneous Income, Net
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ (599)	$ 70	$ (665)	$ 70