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CONTINGENCIES AND COMMITMENTS (Details Textuals) (USD $) In Thousands, unless otherwise specified	12 Months Ended			1 Months Ended		12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009	Oct. 11, 2007 Federal Securities Class Actions [Member]	Oct. 11, 2007 Shareholder Derivative Lawsuits [Member]	Jul. 31, 2007 Ann Arbor Michigan Site [Member]	Jul. 31, 2002 Ann Arbor Michigan Site [Member]	Jul. 31, 2001 Ann Arbor Michigan Site [Member]	Jul. 31, 2000 Ann Arbor Michigan Site [Member]	Jul. 31, 2011 Ann Arbor Michigan Site [Member]
Number of lawsuits filed against the Company				4	2
Environmental liabilities	$ 15,286
Stipulated penalties enforced for the separate alleged violations of the Consent Judgment								142	4,900
Reimbursement to State for Charges allegedly incurred for groundwater monitoring						494	227
Restructuring Reserve, Current										10,692
Amount added to restructuring reserve	3,817
Settlement Liability		2,000
Surety outstanding bonds relating primarily to long-term contracts with governmental agencies	144,478
Rent expenses for all operating leases	33,682	33,601	31,601
Minimum rental commitments for all non-cancelable operating leases due in 2012	27,045
Minimum rental commitments for all non-cancelable operating leases due in 2013	17,827
Minimum rental commitments for all non-cancelable operating leases due in 2014	12,095
Minimum rental commitments for all non-cancelable operating leases due in 2015	5,879
Minimum rental commitments for all non-cancelable operating leases due in 2016	3,822
Minimum rental commitments for all non-cancelable operating leases due in 2017 and thereafter	6,238
Non-cancelable future purchase commitments for goods or services with various vendors due in 2012	91,039
Non-cancelable future purchase commitments for goods or services with various vendors due in 2013	10,990
Non-cancelable future purchase commitments for goods or services with various vendors due in 2014	3,545
Non-cancelable future purchase commitments for goods or services with various vendors due in 2015	404
Non-cancelable future purchase commitments for goods or services with various vendors due in 2016	302
Non-cancelable future purchase commitments for goods or services with various vendors due in 2017 and thereafter	$ 2,033