Segment Reporting (Summary Of Segment Detail) (Details) (USD $) In Thousands	3 Months Ended								12 Months Ended
	Jul. 31, 2011	Apr. 30, 2011	Jan. 31, 2011	Oct. 31, 2010	Jul. 31, 2010	Apr. 30, 2010	Jan. 31, 2010	Oct. 31, 2009	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Net sales	$ 625,450	$ 594,565	$ 537,105	$ 536,909	$ 515,243	$ 497,619	$ 436,122	$ 428,080	$ 2,294,029	$ 1,877,064	$ 1,868,629
Depreciation and amortization									60,491	59,232	58,597
Equity earnings in unconsolidated affiliates									4,105	2,019	2,266
Earnings before income taxes									312,263	230,176	161,425
Assets	1,726,093				1,499,506				1,726,093	1,499,506	1,333,996
Equity investments in unconsolidated affiliates	19,177				15,485				19,177	15,485	15,991
Capital expenditures, net of acquired businesses									60,633	43,149	46,080
Engine Products [Member]
Net sales									1,440,495	1,126,007	1,027,685
Depreciation and amortization									36,338	33,433	32,287
Equity earnings in unconsolidated affiliates									3,302	1,859	2,172
Earnings before income taxes									211,255	155,833	85,896
Assets	888,080				702,300				888,080	702,300	631,278
Equity investments in unconsolidated affiliates	16,619				14,860				16,619	14,860	15,474
Capital expenditures, net of acquired businesses									36,423	24,355	25,390
Industrial Products [Member]
Net sales									853,534	751,057	840,944
Depreciation and amortization									19,396	20,935	20,386
Equity earnings in unconsolidated affiliates									803	160	94
Earnings before income taxes									123,871	91,084	87,427
Assets	519,730				477,154				519,730	477,154	474,291
Equity investments in unconsolidated affiliates	2,558				625				2,558	625	517
Capital expenditures, net of acquired businesses									19,442	15,250	16,032
Corporate & Unallocated [Member]
Net sales
Depreciation and amortization									4,757	4,864	5,924
Equity earnings in unconsolidated affiliates
Earnings before income taxes									(22,863)	(16,741)	(11,898)
Assets	318,283				320,052				318,283	320,052	228,427
Equity investments in unconsolidated affiliates
Capital expenditures, net of acquired businesses									$ 4,768	$ 3,544	$ 4,658