Combined Financial Results for Unconsolidated Affiliates (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2013	Feb. 29, 2012
Investments in and Advances to Affiliates [Line Items]
Net sales	$ 421,645	$ 409,981	$ 1,306,758	$ 1,258,185
Gross margin	90,570	82,904	254,796	246,714
Operating income	61,387	56,219	169,997	166,257
Depreciation and amortization	9,979	8,431	29,089	25,164
Interest expense	2,212	1,925	6,681	3,751
Income tax expense	1,842	1,908	5,488	12,032
Net earnings	$ 57,421	$ 51,955	$ 158,570	$ 151,779