Consolidated Statements of Earnings (USD $)
In Thousands, except Per Share data, unless otherwise specified
 3 Months Ended 9 Months Ended
Feb. 28, 2014
Feb. 28, 2013
Feb. 28, 2014
Feb. 28, 2013
Net sales $ 773,230 $ 619,527 $ 2,235,421 $ 1,908,184
Cost of goods sold 650,743 522,501 1,873,738 1,622,651
Gross margin 122,487 97,026 361,683 285,533
Selling, general and administrative expense 75,680 63,221 225,615 187,744
Impairment of long-lived assets     35,375 1,520
Restructuring and other expense (income) 1,398 146 (3,781) 1,811
Joint venture transactions 120 253 1,048 (1,188)
Operating income 45,289 33,406 103,426 95,646
Other income (expense):        
Miscellaneous income 488 596 13,897 1,064
Interest expense (6,196) (6,158) (18,694) (17,751)
Equity in net income of unconsolidated affiliates 21,186 25,716 69,223 73,580
Earnings before income taxes 60,767 53,560 167,852 152,539
Income tax expense 16,556 16,229 38,948 47,721
Net earnings 44,211 37,331 128,904 104,818
Net earnings attributable to noncontrolling interest 3,608 200 10,767 1,899
Net earnings attributable to controlling interest $ 40,603 $ 37,131 $ 118,137 $ 102,919
Basic        
Average common shares outstanding 68,895 69,791 69,268 68,998
Earnings per share attributable to controlling interest $ 0.59 $ 0.53 $ 1.71 $ 1.49
Diluted        
Average common shares outstanding 71,528 71,914 71,910 70,501
Earnings per share attributable to controlling interest $ 0.57 $ 0.52 $ 1.64 $ 1.46
Common shares outstanding at end of period 68,302 70,168 68,302 70,168
Cash dividends declared per share $ 0.15 $ 0.26 $ 0.45 $ 0.52