Income Taxes (Schedule Of Components Of Total Current Income Tax Expense) (Details) (USD $) In Thousands	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2009
Income Taxes
Federal tax expense at statutory rates	$ 53,420	$ 59,988	$ 8,188
State tax expense at various state tax rates (net of federal benefit)	956	5,153	738
Current tax expense effect of accrued product warranties	1,698	3,622	(7,253)
Current tax expense effect of other temporary items	1,989	(407)	842
Income tax credits and incentives	(2,421)	(1,069)	(3,669)
Amended returns and tax exam settlements			(1,022)
Domestic production activities deduction	(5,236)	(3,745)	(420)
Executive compensation limitation		1,578
Goodwill impairment			3,707
Tax-exempt interest	(8)	(55)	(444)
Change in uncertain tax positions	(1,426)	(1,931)	1,271
True-up of current tax payable	(1,169)	807	(2,308)
Other permanent items	1,390	847	211
Total Current Income Taxes	$ 49,193	$ 64,788	$ (159)

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Current Tax Expense Effect Of Other Temporary Items

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Income Tax Expense Permanent Tax Differences

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Income Tax Reconciliation Executive Compensation Limitation

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Increase Decrease In Liability For Uncertain Tax Positions

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State Tax Expense Net Of Federal Benefits

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The component of income tax expense for the period representing amounts of income taxes paid or payable (or refundable) for the period for all income tax obligations as determined by applying the provisions of relevant enacted tax laws to relevant amounts of taxable Income or Loss from continuing operations.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to the deduction for qualified production activities received under enacted tax laws.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to nondeductible impairment losses under enacted tax laws.

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The sum of the differences between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to tax credits.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to income that is exempt from income taxes under enacted tax laws.

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The sum of the differences between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to all income tax settlements for the period.

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The increase (decrease) during the period in the amount due for taxes based on the reporting entity's earnings or attributable to the entity's income earning process (business presence) within a given jurisdiction.

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