Segment Reporting (Summary Of Segment Detail) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2013	Apr. 30, 2012	Jul. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 619,371	$ 647,237	$ 1,804,354	$ 1,836,415
Earnings before income taxes	99,476	99,990	247,003	268,426
Assets	1,757,608	1,754,273	1,757,608	1,754,273	1,730,082
Engine Products [Member]
Segment Reporting Information [Line Items]
Net sales	383,314	407,041	1,107,814	1,171,600
Earnings before income taxes	65,680	62,136	152,129	170,432
Assets	815,604	879,228	815,604	879,228
Industrial Products [Member]
Segment Reporting Information [Line Items]
Net sales	236,057	240,196	696,540	664,815
Earnings before income taxes	37,555	38,792	102,709	103,688
Assets	539,151	534,686	539,151	534,686
Corporate & Unallocated [Member]
Segment Reporting Information [Line Items]
Earnings before income taxes	(3,759)	(938)	(7,835)	(5,694)
Assets	$ 402,853	$ 340,359	$ 402,853	$ 340,359