Schedule of Combined Financial Information for Unconsolidated Affiliates (Detail) - USD ($) $ in Thousands		3 Months Ended
		Aug. 31, 2015	Aug. 31, 2014	May. 31, 2015
Investments in and Advances to Affiliates [Line Items]
Cash		$ 96,400		$ 101,011
Receivable from member	[1]	10,213		11,092
Other current assets		477,072		491,507
Noncurrent assets		331,811		318,939
Total assets		915,496		922,549
Current liabilities		141,720		184,028
Short-term borrowings		25,483
Current maturities of long-term debt		4,460		4,489
Long-term debt		270,771		272,861
Other noncurrent liabilities		20,205		20,471
Equity		452,857		440,700
Total liabilities and equity		915,496		$ 922,549
Net sales		404,463	$ 392,550
Gross margin		89,018	88,751
Operating income		61,246	63,479
Depreciation and amortization		8,097	9,122
Interest expense		2,159	2,162
Income tax expense		2,560	2,753
Net earnings		$ 62,926	$ 59,440

[1] Represents cash owed from a joint venture partner as a result of centralized cash management.