Provision For Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jan. 31, 2012	Jul. 31, 2011	Jan. 31, 2011	Jan. 31, 2012	Jan. 31, 2011
Provision For Income Taxes [Abstract]
Maximum percentage of tax benefits realized upon ultimate settlement				50.00%
Remaining unrecognized tax benefits income tax penalties and interest accrued		$ 366		$ 734
Anticipated decrease in unrecognized tax benefits				3,500
Accrued interest and penalties related to unrecognized tax benefits	$ 800			$ 800
Effective income tax rate	36.40%		22.90%	35.80%	28.60%

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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