Schedule of Combined Financial Information for Unconsolidated Affiliates (Detail) - Unconsolidated Affiliates - USD ($) $ in Thousands	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015	May 31, 2016
Investments in and Advances to Affiliates [Line Items]
Cash	$ 51,269		$ 112,122
Other current assets	513,318		446,796
Noncurrent assets	355,777		352,370
Total assets	920,364		911,288
Current liabilities	125,082		112,491
Short-term borrowings	8,315		11,398
Current maturities of long-term debt	2,913		3,297
Long-term debt	265,301		266,942
Other noncurrent liabilities	22,678		21,034
Equity	496,075		496,126
Total liabilities and equity	920,364		$ 911,288
Net sales	417,115	$ 404,463
Gross margin	124,197	89,018
Operating income	94,397	61,246
Depreciation and amortization	6,820	8,097
Interest expense	2,148	2,159
Income tax expense	7,518	2,560
Net earnings	$ 86,067	$ 62,926