Segment Reporting (Summary Of Segment Detail) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Jul. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 588,947	$ 608,295
Earnings before income taxes	76,678	92,017
Assets	1,712,498	1,746,171	1,730,082
Engine Products [Member]
Segment Reporting Information [Line Items]
Net sales	370,660	393,725
Earnings before income taxes	47,424	59,878
Assets	818,480	882,967
Industrial Products [Member]
Segment Reporting Information [Line Items]
Net sales	218,287	214,570
Earnings before income taxes	32,562	34,299
Assets	539,894	521,984
Corporate & Unallocated [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes	(3,308)	(2,160)
Assets	$ 354,124	$ 341,220