Segment Reporting (Summary Of Segment Detail) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2013	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Segment Reporting Information [Line Items]
Net sales	$ 610,578	$ 575,588	$ 588,537	$ 596,510	$ 668,226	$ 624,234	$ 581,622	$ 599,384	$ 2,371,213	$ 2,473,466	$ 2,436,948
Depreciation and amortization									74,298	67,163	64,290
Equity earnings in unconsolidated affiliates									5,110	6,536	4,693
Earnings before income taxes		$ 67,849	$ 65,424						288,603	360,703	348,181
Assets	1,809,534				1,942,411				1,809,534	1,942,411	1,743,556
Equity investments in unconsolidated affiliates	18,344				21,398				18,344	21,398	18,840
Capital expenditures									93,739	97,210	94,895
Engine Products [Member]
Segment Reporting Information [Line Items]
Net sales									1,484,132	1,584,027	1,504,188
Depreciation and amortization									43,279	38,925	35,815
Equity earnings in unconsolidated affiliates									4,134	5,596	4,000
Earnings before income taxes									186,274	233,920	220,892
Assets	887,698				900,083				887,698	900,083	826,151
Equity investments in unconsolidated affiliates	15,120				17,439				15,120	17,439	15,563
Capital expenditures									54,604	56,340	52,864
Corporate And Unallocated [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization									4,611	4,296	6,028
Earnings before income taxes									(21,033)	(7,195)	(11,819)
Assets	287,859				470,328				287,859	470,328	389,989
Capital expenditures									5,817	6,218	8,897
Industrial Products [Member]
Segment Reporting Information [Line Items]
Net sales									887,081	889,439	932,760
Depreciation and amortization									26,408	23,942	22,447
Equity earnings in unconsolidated affiliates									976	940	693
Earnings before income taxes									123,362	133,978	139,108
Assets	633,977				572,000				633,977	572,000	527,416
Equity investments in unconsolidated affiliates	$ 3,224				$ 3,959				3,224	3,959	3,277
Capital expenditures									$ 33,318	$ 34,652	$ 33,134