Schedule of Combined Financial Information for Unconsolidated Affiliates (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Feb. 28, 2015		Feb. 28, 2014	Feb. 28, 2015		Feb. 28, 2014	May 31, 2014
Investments in and Advances to Affiliates [Line Items]
Cash	$ 48,422			$ 48,422			$ 52,997
Receivable from member	10,865	[1]		10,865	[1]		12,717	[1]
Other current assets	462,631			462,631			454,417
Noncurrent assets	286,170			286,170			294,001
Total assets	808,088			808,088			814,132
Current liabilities	131,216			131,216			128,595
Short-term borrowings	38,324			38,324			40,992
Current maturities of long-term debt	4,480			4,480			4,510
Long-term debt	264,982			264,982			268,350
Other noncurrent liabilities	20,407			20,407			20,217
Equity	348,679			348,679			351,468
Total liabilities and equity	808,088			808,088			814,132
Net sales	356,604		340,645	1,137,866		1,121,362
Gross margin	67,636		73,217	232,580		239,098
Operating income	41,335		48,752	154,678		164,824
Depreciation and amortization	8,827		8,622	26,932		28,063
Interest expense	2,157		2,494	6,492		6,950
Income tax expense	2,555		2,937	8,107		8,829
Net earnings	$ 37,859		$ 44,018	$ 141,789		$ 149,801

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