Supplementary Balance Sheet Information (Composition Of Property, Plant And Equipment) (Details) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2012	Jul. 31, 2011	Apr. 30, 2011
Supplementary Balance Sheet Information [Abstract]
Land and land improvements	$ 282,038	$ 271,742	$ 270,965
Buildings and building improvements	835,291	801,582	801,268
Machinery and equipment	566,466	539,983	542,582
Furniture and fixtures	240,367	215,862	211,839
Software	80,591	64,408	63,925
Vehicles	44,536	40,627	41,968
Construction in progress	26,341	34,638	22,314
Gross property, plant and equipment	2,075,630	1,968,842	1,954,861
Accumulated depreciation	(1,019,387)	(947,106)	(927,557)
Property, plant and equipment, net	$ 1,056,243	$ 1,021,736	$ 1,027,304