Acquisitions and Divestitures (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Summary of the combined estimated fair values of the assets acquired and liabilities assumed at the date of the acquisition
Current assets net of cash	$ 5,082	$ 1,876	$ 5,313
Property, plant & equipment	2,743	415	743
Goodwill	22,844	4,792	20,266
Total assets acquired net of cash	46,636	9,416	35,632
Liabilities assumed	(8,987)	(1,446)	(5,201)
Debt assumed	1,432
Net cash paid for acquisitions	37,649	7,970	30,431
Customer relationships [Member]
Summary of the combined estimated fair values of the assets acquired and liabilities assumed at the date of the acquisition
Total assets acquired net of cash	8,903	1,846	7,970
Noncompete Agreements [Member]
Summary of the combined estimated fair values of the assets acquired and liabilities assumed at the date of the acquisition
Total assets acquired net of cash	186	487
Trademarks [Member]
Summary of the combined estimated fair values of the assets acquired and liabilities assumed at the date of the acquisition
Total assets acquired net of cash	$ 6,878		$ 1,340