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, 2017	Nov. 30, 2016	Nov. 30, 2017	Nov. 30, 2016
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ (67)	$ 1,404	$ 2,059	$ 4,246
Commodity Contracts | Cost of Goods Sold
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	(86)	2,003	2,248	4,911
Foreign Currency Contracts | Miscellaneous Income, Net
Derivative [Line Items]
Gain (Loss) Recognized in Earnings	$ 19	$ (599)	$ (189)	$ (665)