Segment Reporting (Summary Of Segment Detail) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 31, 2011	Oct. 31, 2010	Jul. 31, 2011
Segment Reporting Information [Line Items]
Net sales	$ 608,295	$ 536,909
Earnings before income taxes	92,017	71,957
Assets	1,746,171	1,590,486	1,726,093
Engine Products [Member]
Segment Reporting Information [Line Items]
Net sales	393,725	333,769
Earnings before income taxes	59,878	48,451
Assets	882,967	750,951
Industrial Products [Member]
Segment Reporting Information [Line Items]
Net sales	214,570	203,140
Earnings before income taxes	34,299	30,035
Assets	521,984	461,321
Corporate & Unallocated [Member]
Segment Reporting Information [Line Items]
Net sales
Earnings before income taxes	(2,160)	(6,529)
Assets	$ 341,220	$ 378,214