Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Net sales	$ 3,084,660	$ 2,755,508	$ 2,276,557
Cost of products sold	2,727,884	2,422,373	1,969,471
Gross profit	356,776	333,135	307,086
Selling, general and administrative expenses	169,154	180,858	147,407
Impairment of goodwill and trademarks		3,466	500
Amortization of intangible assets	11,135	10,262	510
Gain on involuntary conversion		9,417	7,593
Interest income	3,765	3,910	5,515
Interest expense	560	212	395
Other income, net	999	963	11
Income before income taxes	180,691	152,627	171,393
Income taxes	58,952	46,354	61,329
Net income	121,739	106,273	110,064
Earnings per common share
Basic	$ 2.26	$ 1.92	$ 2.08
Diluted	$ 2.26	$ 1.92	$ 2.07
Net income	121,739	106,273	110,064
Unrealized appreciation on investments, net of tax effects of $6, $158 and $231	7	257	368
Foreign currency translation adjustment, net of tax effects of $0, $0 and $1,080			(1,762)
Total other comprehensive income (loss)	7	257	(1,394)
Comprehensive income	$ 121,746	$ 106,530	$ 108,670