Schedule of Combined Financial Information for Unconsolidated Affiliates (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Aug. 31, 2013		Aug. 31, 2012	May 31, 2013
Investments in and Advances to Affiliates [Line Items]
Cash	$ 55,310			$ 70,380
Receivable from partner	4,069	[1]		69,706	[1]
Other current assets	426,039			518,262
Noncurrent assets	302,187			350,681
Total assets	787,605			1,009,029
Current liabilities	113,229			181,111
Short-term borrowings	14,293			21,369
Current maturities of long-term debt	5,265			5,442
Long-term debt	272,574			274,750
Other noncurrent liabilities	18,613			18,345
Equity	363,631			508,012
Total liabilities and equity	787,605			1,009,029
Net sales	423,481		446,853
Gross margin	89,814		74,513
Operating income	64,540		51,711
Depreciation and amortization	10,337		8,990
Interest expense	2,223		2,261
Income tax expense	3,030		3,469
Net earnings	$ 59,634		$ 46,284

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