Summary of Unaudited Quarterly Consolidated Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	May 31, 2014	Feb. 28, 2014	Nov. 30, 2013	Aug. 31, 2013	May 31, 2013	Feb. 28, 2013	Nov. 30, 2012	Aug. 31, 2012	May 31, 2014	May 31, 2013	May 31, 2012
Quarterly Financial Information [Line Items]
Net sales	$ 891,005	$ 773,230	$ 769,900	$ 692,291	$ 704,060	$ 619,527	$ 622,622	$ 666,035	$ 3,126,426	$ 2,612,244	$ 2,534,701
Gross margin	130,836	122,487	128,232	110,964	111,110	97,026	94,856	93,651	492,519	396,643	332,868
Net earnings attributable to controlling interest	$ 33,163	$ 40,603	$ 22,977	$ 54,557	$ 33,523	$ 37,131	$ 31,826	$ 33,962	$ 151,300	$ 136,442	$ 115,595
Earnings per share - basic	$ 0.49	$ 0.59	$ 0.33	$ 0.78	$ 0.48	$ 0.53	$ 0.46	$ 0.50	$ 2.19	$ 1.97	$ 1.66
Earnings per share - diluted	$ 0.47	$ 0.57	$ 0.32	$ 0.76	$ 0.46	$ 0.52	$ 0.45	$ 0.49	$ 2.11	$ 1.91	$ 1.65